Step-by-step explanation:
The fraction she will complete is 1/2 / 3/5 = 1/2 * 5/3 = 5/6 completed
help pls xxxxxxxxxxx
Answer:
inside the c circle put 12 inside the d circle put 7 and inside the middle put 19 or 15 and inside rectangle put 30
Isabella wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 61 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 14.3 and a standard deviation of 2.2. What is the 98% confidence interval for the number of chocolate chips per cookie for Big Chip cookies
The 98% confidence interval for the number of chocolate chips per cookie in Big Chip cookies is approximately 13.5529 to 15.0471 chips.
To find the 98% confidence interval for the number of chocolate chips per cookie in Big Chip cookies, we'll use the t-distribution since the sample size is relatively small (n = 61) and we don't know the population standard deviation.
The formula for the confidence interval is:
[tex]CI = \bar X \pm t_{critical} \times \dfrac{s } {\sqrt{n}}[/tex]
where:
X is the sample mean,
[tex]t_{critical[/tex] is the critical value for the t-distribution corresponding to the desired confidence level (98% in this case),
s is the sample standard deviation,
n is the sample size.
First, let's find the critical value for the t-distribution at a 98% confidence level with (n-1) degrees of freedom (df = 61 - 1 = 60). You can use a t-table or a calculator to find this value. For a two-tailed 98% confidence level, the critical value is approximately 2.660.
Given data:
X (sample mean) = 14.3
s (sample standard deviation) = 2.2
n (sample size) = 61
[tex]t_{critical[/tex] = 2.660 (from the t-distribution table)
Now, calculate the confidence interval:
[tex]CI = 14.3 \pm 2.660 \times \dfrac{2.2} { \sqrt{61}}\\CI = 14.3 \pm 2.660 \times \dfrac{2.2} { 7.8102}\\CI = 14.3 \pm 0.7471[/tex]
Lower bound = 14.3 - 0.7471 ≈ 13.5529
Upper bound = 14.3 + 0.7471 ≈ 15.0471
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Prove the following theorems using only the primitive rules (CP,MP,MT,DN,VE,VI,&I,&E,RAA<->df).
"turnstile" P->PvQ
"turnstile" (Q->R)->((P->Q)->(P->R))
"turnstile" P->(Q->(P&Q))
"turnstile" (P->R)->((Q->R)->(PvQ->R))
"turnstile" ((P->Q)&-Q)->-P
"turnstile" (-P->P)->P
To prove the given theorems using only the primitive rules, we will use the following rules of inference:
Conditional Proof (CP)
Modus Ponens (MP)
Modus Tollens (MT)
Double Negation (DN)
Disjunction Introduction (DI)
Disjunction Elimination (DE)
Conjunction Introduction (CI)
Conjunction Elimination (CE)
Reductio ad Absurdum (RAA)
Biconditional Definition (<->df)
Now let's prove each of the theorems:
"turnstile" P -> PvQ
Proof:
| P (Assumption)
| PvQ (DI 1)
P -> PvQ (CP 1-2)
"turnstile" (Q -> R) -> ((P -> Q) -> (P -> R))
Proof:
| Q -> R (Assumption)
| P -> Q (Assumption)
|| P (Assumption)
||| Q (Assumption)
||| R (MP 1, 4)
|| Q -> R (CP 4-5)
|| P -> (Q -> R) (CP 3-6)
| (P -> Q) -> (P -> R) (CP 2-7)
(Q -> R) -> ((P -> Q) -> (P -> R)) (CP 1-8)
"turnstile" P -> (Q -> (P & Q))
Proof:
| P (Assumption)
|| Q (Assumption)
|| P & Q (CI 1, 2)
| Q -> (P & Q) (CP 2-3)
P -> (Q -> (P & Q)) (CP 1-4)
"turnstile" (P -> R) -> ((Q -> R) -> (PvQ -> R))
Proof:
| P -> R (Assumption)
| Q -> R (Assumption)
|| PvQ (Assumption)
||| P (Assumption)
||| R (MP 1, 4)
|| Q -> R (CP 4-5)
||| Q (Assumption)
||| R (MP 2, 7)
|| R (DE 3, 4-5, 7-8)
| PvQ -> R (CP 3-9)
(P -> R) -> ((Q -> R) -> (PvQ -> R)) (CP 1-10)
"turnstile" ((P -> Q) & -Q) -> -P
Proof:
| (P -> Q) & -Q (Assumption)
|| P (Assumption)
|| Q (MP 1, 2)
|| -Q (CE 1)
|| |-P (RAA 2-4)
| -P (RAA 2-5)
((P -> Q) & -Q) -> -P (CP 1-6)
"turnstile" (-P -> P) -> P
Proof:
| -P -> P (Assumption)
|| -P (Assumption)
|| P (MP 1, 2)
|-P -> P
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Many patients get concerned when exposed to in day-to-day activities. t(hrs) 0 3 5 R 1 a test involves injection of a radioactive material. For example for scanning a gallbladder, a few drops of Technetium-99m isotope is used. However, it takes about 24 hours for the radiation levels to reach what we are Below is given the relative intensity of radiation as a function of time. 7 9 1.000 0.891 0.708 0.562 0.447 0.355 The relative intensity is related to time by the equation R = A e^(Bt). Find the constant A by the least square method. (correct to 4 decimal places)
The constant A, obtained using the least squares method, is 0.5698.
To find the constant A using the least squares method, we need to fit the given data points (t, R) to the equation R = A * e^(Bt) by minimizing the sum of the squared residuals.
Let's set up the equations for the least squares method:
Take the natural logarithm of both sides of the equation:
ln(R) = ln(A * e^(Bt))
ln(R) = ln(A) + Bt
Define new variables:
Let Y = ln(R)
Let X = t
Let C = ln(A)
The equation now becomes:
Y = C + BX
We can now apply the least squares method to find the best-fit line for the transformed variables.
Using the given data points (t, R):
(t, R) = (0, 1.000), (3, 0.891), (5, 0.708), (7, 0.562), (9, 0.447), (1, 0.355)
We can calculate the transformed variables Y and X:
Y = ln(R) = [0, -0.113, -0.345, -0.578, -0.808, -1.035]
X = t = [0, 3, 5, 7, 9, 1]
Calculate the sums:
ΣY = -2.879
ΣX = 25
ΣY^2 = 2.847
ΣXY = -14.987
Use the least squares formulas to calculate B and C:
B = (6ΣXY - ΣXΣY) / (6ΣX^2 - (ΣX)^2)
C = (1/6)ΣY - B(1/6)ΣX
Plugging in the values:
B = (-14.987 - (25)(-2.879)) / (6(2.847) - (25)^2)
B = -0.1633
C = (1/6)(-2.879) - (-0.1633)(1/6)(25)
C = -0.5636
Finally, we can calculate A using the relationship A = e^C:
A = e^(-0.5636)
A ≈ 0.5698 (rounded to 4 decimal places)
Therefore, the constant A, obtained using the least squares method, is approximately 0.5698.
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Use two arbitrary 2-dimensional vectors to verify: If vectors u
and v are orthogonal, then
u2+ν2=u-v2.
Here, u2is the length squared of u.
The statement "If vectors u and v are orthogonal, then u² + v² = (u - v)²" is not true in general.
What is the dot product of two arbitrary 3-dimensional vectors u and v?To verify the given statement, let's consider two arbitrary 2-dimensional vectors:
Vector u: (u₁, u₂)
Vector v: (v₁, v₂)
The length squared of vector u, denoted as u², is given by:
u² = u₁² + u₂²
According to the statement, if vectors u and v are orthogonal, then:
u² + v² = (u - v)²
Expanding the right side of the equation:
(u - v)² = (u₁ - v₁)² + (u₂ - v₂)²
= u₁² - 2u₁v₁ + v₁² + u₂² - 2u₂v₂ + v₂²
= u₁² + u₂² - 2u₁v₁ - 2u₂v₂ + v₁² + v₂²
Comparing this with the left side of the equation (u² + v²), we can see that they are not equal. There is a missing cross term (-2u₁v₁ - 2u₂v₂) on the left side. Therefore, the statement is not true in general.
In other words, if vectors u and v are orthogonal, it does not imply that u² + v² is equal to (u - v)².
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Let f(x)= 1/2 x^4 −4x^3 For what values of x does the graph of f have a point of inflection? Choose all answers that apply: x=0 x=4 x=8 f has no points of inflection.
x = 4 is the point of inflection on the curve.
The second derivative of f(x) = 1/2 x^4 - 4x^3 is f''(x) = 6x^2 - 24x.
To find the critical points, we set f''(x) = 0, which gives us the equation 6x(x - 4) = 0.
Solving for x, we find x = 0 and x = 4 as the critical points.
We evaluate the second derivative of f(x) at different intervals to determine the sign of the second derivative. Evaluating f''(-1), f''(1), f''(5), and f''(9), we find that the sign of the second derivative changes when x passes through 4.
Therefore, The point of inflection on the curve is x = 4.
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A recording company obtains the blank CDs used to produce its labels from three compact disk manufacturens 1 , II, and III. The quality control department of the company has determined that 3% of the compact disks prodised by manufacturer I are defective. 5% of those prodoced by manufacturer II are defective, and 5% of those prodoced by manaficturer III are defective. Manufacturers 1, 1I, and III supply 36%,54%, and 10%. respectively, of the compact disks used by the company. What is the probability that a randomly selected label produced by the company will contain a defective compact disk? a) 0.0050 b) 0.1300 c) 0.0270 d) 0.0428 e) 0.0108 fI None of the above.
The probability of selecting a defective compact disk from a randomly chosen label produced by the company is 0.0428 or 4.28%. The correct option is d.
To find the probability of a randomly selected label produced by the company containing a defective compact disk, we need to consider the probabilities of each manufacturer's defective compact disks and their respective supply percentages.
Let's calculate the probability:
1. Manufacturer I produces 36% of the compact disks, and 3% of their disks are defective. So, the probability of selecting a defective disk from Manufacturer I is (36% * 3%) = 0.36 * 0.03 = 0.0108.
2. Manufacturer II produces 54% of the compact disks, and 5% of their disks are defective. The probability of selecting a defective disk from Manufacturer II is (54% * 5%) = 0.54 * 0.05 = 0.0270.
3. Manufacturer III produces 10% of the compact disks, and 5% of their disks are defective. The probability of selecting a defective disk from Manufacturer III is (10% * 5%) = 0.10 * 0.05 = 0.0050.
Now, we can find the total probability by summing up the probabilities from each manufacturer:
Total probability = Probability from Manufacturer I + Probability from Manufacturer II + Probability from Manufacturer III
= 0.0108 + 0.0270 + 0.0050
= 0.0428
Therefore, the probability that a randomly selected label produced by the company will contain a defective compact disk is 0.0428. Hence, the correct option is (d) 0.0428.
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(6) Show that if B = PAP-¹ for some invertible matrix P then B = PAKP-1 for all integers k, positive and negative.
B = PAKP⁻¹ holds for k + 1. By induction, we conclude that B = PAKP⁻¹ for all integers k, positive and negative.
Let's prove that if B = PAP⁻¹ for some invertible matrix P, then B = PAKP⁻¹ for all integers k, positive and negative.
Let P be an invertible matrix, and let B = PAP⁻¹. Now, consider an arbitrary integer k, positive or negative. Our goal is to show that B = PAKP⁻¹. We will proceed by induction on k.
Base case: k = 0.
In this case, P⁰ = I, where I represents the identity matrix. Thus, B = P⁰AP⁰⁻¹ = AI = A = P⁰AP⁰⁻¹ = PAP⁻¹. Hence, B = PAKP⁻¹ holds for k = 0.
Induction step:
Assume that B = PAKP⁻¹ holds for some integer k. We aim to show that B = PA(k+1)P⁻¹ also holds. Using the induction hypothesis, we have B = PAKP⁻¹. Multiplying both sides by A, we obtain AB = PAKAP⁻¹ = PA(k+1)P⁻¹. Then, multiplying both sides by P⁻¹, we get B = PAKP⁻¹ = PA(k+1)P⁻¹.
Therefore, B = PAKP⁻¹ holds for k + 1. By induction, we conclude that B = PAKP⁻¹ for all integers k, positive and negative.
In summary, we have shown that B = PAKP⁻¹ for all integers k, positive and negative.
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Calculate the truth value of the following:
(~(0~1) v 1)
0
?
1
The truth value of the expression (~(0 ~ 1) v 1) 0?1 is false.
To calculate the truth value of the expression, let's break it down step by step:
(~(0 ~ 1) v 1) 0?1Let's evaluate the innermost part of the expression first: (0 ~ 1). The tilde (~) represents negation, so ~(0 ~ 1) means not (0 ~ 1).~(0 ~ 1) evaluates to ~(0 or 1). In classical logic, the expression (0 or 1) is always true since it represents a logical disjunction where at least one of the operands is true. Therefore, ~(0 or 1) is false.Now, we have (~F v 1) 0?1, where F represents false.According to the order of operations, we evaluate the conjunction (0?1) first. In classical logic, the expression 0?1 represents the logical AND operation. However, in this case, we have a 0 as the left operand, which means the overall expression will be false regardless of the value of the right operand.Therefore, (0?1) evaluates to false.Substituting the values, we have (~F v 1) false.Let's evaluate the disjunction (~F v 1). The disjunction (or logical OR) is true when at least one of the operands is true. Since F represents false, ~F is true, and true v 1 is true.Finally, we have true false, which evaluates to false.So, the truth value of the expression (~(0 ~ 1) v 1) 0?1 is false.
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Find an equation that has the solutions: y=1/7,y=7 Write your answer in standard form. Equation:
The equation in a standard form that has the solutions y = 1/7 and y = 7.
To find an equation with the given solutions y = 1/7 and y = 7, we can use the fact that the solutions of a quadratic equation are given by the formula:
y = ax^2 + bx + c
We know that the solutions are y = 1/7 and y = 7, so we can set up two equations based on these solutions:
1/7 = a(1/7)^2 + b(1/7) + c -- Equation 1
7 = a(7)^2 + b(7) + c -- Equation 2
Simplifying Equation 1:
1/7 = a/49 + b/7 + c
Multiplying through by 49 to eliminate the fractions:
7 = a + 7b + 49c
Simplifying Equation 2:
7 = 49a + 7b + c
Now, we have a system of linear equations:
7 = a + 7b + 49c -- Equation 3
7 = 49a + 7b + c -- Equation 4
To eliminate variables, we can subtract Equation 3 from Equation 4:
0 = 48a - 48c
Dividing by 48:
0 = a - c
We can substitute this value back into Equation 3:
7 = (a - c) + 7b + 49c
Simplifying:
7 = a + 7b + 48c
Now, we have a simplified equation that satisfies both solutions:
a + 7b + 48c = 7
This is the equation in a standard form that has the solutions y = 1/7 and y = 7.
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Find the matrix A′ for T relative to the basis B′
a. T: R2 ⟶ R2, T(x, y) = (2x − y, y − x);B′ = {(1, −2),
(0,3)}
b. T: R3 ⟶ R3, T(x, y, z) = (x, y, z);B′ = {(1,1,0), (1,0,1),
(0,1,1)
The matrix A' for T relative to the basis B' is:
[[2, -1],
[-1, 1]]
To find the matrix A' for T relative to the basis B', we need to determine how T acts on each vector in B'.
In the given problem (a), T: R2 ⟶ R2, T(x, y) = (2x − y, y − x), and B' = {(1, −2), (0, 3)}.
We can start by applying T to each vector in B' and expressing the results as linear combinations of the vectors in B'.
For the first vector (1, -2):
T(1, -2) = (2(1) - (-2), (-2) - 1) = (4, -3) = 4(1, -2) + (-3)(0, 3)
For the second vector (0, 3):
T(0, 3) = (2(0) - 3, 3 - 0) = (-3, 3) = (-3)(1, -2) + 2(0, 3)
From the above calculations, we can see that T(1, -2) can be expressed as a linear combination of the vectors in B' with coefficients 4 and -3, and T(0, 3) can be expressed as a linear combination of the vectors in B' with coefficients -3 and 2.
Therefore, the matrix A' for T relative to the basis B' is:
[[4, -3],
[-3, 2]]
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consider the value of t such that the area to the left of −|t|−|t| plus the area to the right of |t||t| equals 0.010.01.
The value of t such that the area to the left of −|t| plus the area to the right of |t| equals 0.01 is: t = −|t1| + 0.005 = −0.245 (approx)
Let’s consider the value of t such that the area to the left of −|t|−|t| plus the area to the right of |t||t| equals 0.01. Now, we know that the area under the standard normal distribution curve between z = 0 and any positive value of z is 0.5. Also, the total area under the standard normal distribution curve is 1.Using this information, we can calculate the value of t such that the area to the left of −|t| is equal to the area to the right of |t|. Let’s call this value of t as t1.So, we have:
Area to the left of −|t1| = 0.5 (since |t1| is positive)
Area to the right of |t1| = 0.5 (since |t1| is positive)
Therefore, the total area between −|t1| and |t1| is 1. We need to find the value of t such that the total area between −|t| and |t| is 0.01. This means that the total area to the left of −|t| is 0.005 and the total area to the right of |t| is also 0.005.
Now, we can calculate the value of t as follows:
Area to the left of −|t1| = 0.5
Area to the left of −|t| = 0.005
Therefore, the area between −|t1| and −|t| is:
Area between −|t1| and −|t| = 0.5 − 0.005 = 0.495
Similarly, the area between |t1| and |t| is:
Area between |t1| and |t| = 1 − 0.495 − 0.005 = 0.5
Area to the right of |t1| = 0.5
Area to the right of |t| = 0.005
Therefore, the value of t such that the area to the left of −|t| plus the area to the right of |t| equals 0.01 is the value of t1 plus the value of t:
−|t1| + |t| = 0.005
2|t1| = 0.5
|t1| = 0.25
Therefore, the value of t such that the area to the left of −|t| plus the area to the right of |t| equals 0.01 is:
t = −|t1| + 0.005 = −0.245 (approx)
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Xander spends most of his time with his 10 closest friends. He has known 4 of his 10 friends since kindergarten. If he is going to see a movie tonight with 3 of his 10 closest friends, what is the probability that the first 2 of the friends to show up to the movie are friends he has known since kindergarten but the third is not? iv been stuke on this one for a bit and im being timed someone plese help me
Answer:
1/10 / 10%
Step-by-step explanation:
This is like the equivalent to a jar with 4 green balls and 6 white balls, where you are picking 3. (The 4 green balls signify the friends from kindergarten.)
You want to solve the probability that the first two balls are green and the third is white.
First draw --> 4 green out of 10 balls --> 4/10 = 2/5
Second draw --> 3 green out of 9 balls --> 3/9 = 1/3
Third draw --> 6 white out of 8 balls --> 6/8 = 3/4
2/5 x 1/3 x 3/4
= 6/60
= 1/10
so the answer is 1/10 (or 10%)
PS I took the quiz
If U = (1,2,3,4,5,6,7,8,9), A = (2,4,6,8), B = (1,3,5,7) verify De Morgan's law.
De Morgan's Law is verified for sets A and B, as the complement of the union of A and B is equal to the intersection of their complements.
De Morgan's Law states that the complement of the union of two sets is equal to the intersection of their complements. In other words:
(A ∪ B)' = A' ∩ B'
Let's verify De Morgan's Law using the given sets:
U = {1, 2, 3, 4, 5, 6, 7, 8, 9}
A = {2, 4, 6, 8}
B = {1, 3, 5, 7}
First, let's find the complement of A and B:
A' = {1, 3, 5, 7, 9}
B' = {2, 4, 6, 8, 9}
Next, let's find the union of A and B:
A ∪ B = {1, 2, 3, 4, 5, 6, 7, 8}
Now, let's find the complement of the union of A and B:
(A ∪ B)' = {1, 3, 5, 7, 9}
Finally, let's find the intersection of A' and B':
A' ∩ B' = {9}
As we can see, (A ∪ B)' = A' ∩ B'. Therefore, De Morgan's Law holds true for the given sets A and B.
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Select the correct answer from the drop-down menu.
Simplify the expression.
4x5y³x3x³y²
6x4y10
=
The simplified expression of the division (4x⁵y³x * 3x³y²) / (6x⁴y¹⁰) is
2x² / y⁵
What is the simplification of the expression?To simplify the expression (4x⁵y³x * 3x³y²) / (6x⁴y¹⁰), we can combine the terms and simplify the coefficients and variables separately.
First, let's simplify the coefficients: 4 * 3 / 6 = 12 / 6 = 2.
Now, let's simplify the variables. For the variable x, we subtract the exponents when dividing: 5 + 1 - 4 = 2. For the variable y, we subtract the exponents: 3 + 2 - 10 = -5.
Therefore, the simplified expression is:
2x² * y⁻⁵
However, we can simplify the expression further by simplifying the negative exponent of y. Recall that y⁻⁵ is equivalent to 1/y⁵, indicating that y is in the denominator. So, we can rewrite the expression as:
2x² / y⁵
Hence, the simplified expression is 2x² / y⁵
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5. A person is parasailing behind a boat.
The cable (string) that attaches them to the boat is 170 feet long.
If the person is 60 feet (up) high.
What is the angle of depression (from the person)?
Round your answer to the nearest tenth of a degree.
H
Р
The angle of depression from the person is approximately 20.2 degrees.
To find the angle of depression, we can consider the triangle formed by the person, the boat, and the vertical line from the person to the water surface. The person is 60 feet above the water, and the cable connecting them to the boat is 170 feet long.
The angle of depression is the angle formed between the cable and the horizontal line. This angle can be found using trigonometry. We can use the tangent function, which is defined as the ratio of the opposite side to the adjacent side.
In this case, the opposite side is the height of the person (60 feet) and the adjacent side is the horizontal distance between the person and the boat. Let's denote this distance as x.
Using the tangent function, we have:
tan(angle) = opposite / adjacent
tan(angle) = 60 / x
To find the value of x, we can use the Pythagorean theorem, which states that the sum of the squares of the two legs of a right triangle is equal to the square of the hypotenuse. In this case, the hypotenuse is the length of the cable (170 feet), and the legs are the height of the person (60 feet) and the horizontal distance (x).
Applying the Pythagorean theorem, we have:
x^2 + 60^2 = 170^2
x^2 + 3600 = 28900
x^2 = 28900 - 3600
x^2 = 25300
x = √25300
x ≈ 159.1 feet
Now, we can substitute the value of x into the tangent equation to find the angle:
tan(angle) = 60 / 159.1
Using a calculator, we can calculate the inverse tangent (arctan) of this ratio:
angle ≈ arctan(60 / 159.1)
angle ≈ 20.2 degrees
As a result, the angle of depression with respect to the person is roughly 20.2 degrees.
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Problem Consider the (real-valued) function f:R 2→R defined by f(x,y)={0x2+y2x3} for (x,y)=(0,0), for (x,y)=(0,0)
(a) Prove that the partial derivatives D1 f:=∂x∂ and D2 f:=∂y∂f are bounded in R2. (Actually, f is continuous! Why?) (b) Let v=(v1,v2)∈R2 be a unit vector. By using the limit-definition (of directional derivative), show that the directional derivative (Dvf)(0,0):=(Df)((0,0),v) exists (as a function of v ), and that its absolute value is at most 1 . [Actually, by using the same argument one can (easily) show that f is Gâteaux differentiable at the origin (0,0).] (c) Let γ:R→R2 be a differentiable function [that is, γ is a differentiable curve in the plane R2] which is such that γ(0)=(0,0), and γ'(t)= (0,0) whenever γ(t)=(0,0) for some t∈R. Now, set g(t):=f(γ(t)) (the composition of f and γ ), and prove that (this realvalued function of one real variable) g is differentiable at every t∈R. Also prove that if γ∈C1(R,R2), then g∈C1(R,R). [Note that this shows that f has "some sort of derivative" (i.e., some rate of change) at the origin whenever it is restricted to a smooth curve that goes through the origin (0,0). (d) In spite of all this, prove that f is not (Fréchet) differentiable at the origin (0,0). (Hint: Show that the formula (Dvf)(0,0)=⟨(∇f)(0,0),v⟩ fails for some direction(s) v. Here ⟨⋅,⋅⟩ denotes the standard dot product in the plane R2). [Thus, f is not (Fréchet) differentiable at the origin (0,0). For, if f were differentiable at the origin, then the differential f′(0,0) would be completely determined by the partial derivatives of f; i.e., by the gradient vector (∇f)(0,0). Moreover, one would have that (Dvf)(0,0)=⟨(∇f)(0,0),v⟩ for every direction v; as discussed in class!]
(a) The partial derivatives D1f and D2f of the function f(x, y) are bounded in R2. Moreover, f is continuous.
(b) The directional derivative (Dvf)(0, 0) exists for a unit vector v, and its absolute value is at most 1. Additionally, f is Gâteaux differentiable at the origin (0, 0).
(c) The function g(t) = f(γ(t)) is differentiable at every t ∈ R, and if γ ∈ C1(R, R2), then g ∈ C1(R, R).
(d) Despite the aforementioned properties, f is not Fréchet differentiable at the origin (0, 0).
(a) To prove that the partial derivatives ∂f/∂x and ∂f/∂y are bounded in R², we need to show that there exists a constant M such that |∂f/∂x| ≤ M and |∂f/∂y| ≤ M for all (x, y) in R².
Calculating the partial derivatives:
∂f/∂x = [tex](0 - 2xy^2)/(x^4 + y^4)[/tex]= [tex]-2xy^2/(x^4 + y^4)[/tex]
∂f/∂y = [tex]2yx^2/(x^4 + y^4)[/tex]
Since[tex]x^4 + y^4[/tex] > 0 for all (x, y) ≠ (0, 0), we can bound the partial derivatives as follows:
|∂f/∂x| =[tex]2|xy^2|/(x^4 + y^4) ≤ 2|x|/(x^4 + y^4) \leq 2(|x| + |y|)/(x^4 + y^4)[/tex]
|∂f/∂y| = [tex]2|yx^2|/(x^4 + y^4) ≤ 2|y|/(x^4 + y^4) \leq 2(|x| + |y|)/(x^4 + y^4)[/tex]
Letting M = 2(|x| + |y|)/[tex](x^4 + y^4)[/tex], we can see that |∂f/∂x| ≤ M and |∂f/∂y| ≤ M for all (x, y) in R². Hence, the partial derivatives are bounded.
Furthermore, f is continuous since it can be expressed as a composition of elementary functions (polynomials, division) which are known to be continuous.
(b) To show the existence and bound of the directional derivative (Dvf)(0,0), we use the limit definition of the directional derivative. Let v = (v1, v2) be a unit vector.
(Dvf)(0,0) = lim(h→0) [f((0,0) + hv) - f(0,0)]/h
= lim(h→0) [f(hv) - f(0,0)]/h
Expanding f(hv) using the given formula: f(hv) = 0(hv²)/(h³) = v²/h
(Dvf)(0,0) = lim(h→0) [v²/h - 0]/h
= lim(h→0) v²/h²
= |v²| = 1
Therefore, the absolute value of the directional derivative (Dvf)(0,0) is at most 1.
(c) Let γ: R → R² be a differentiable curve such that γ(0) = (0,0), and γ'(t) ≠ (0,0) whenever γ(t) = (0,0) for some t ∈ R. We define g(t) = f(γ(t)).
To prove that g is differentiable at every t ∈ R, we can use the chain rule of differentiation. Since γ is differentiable, g(t) = f(γ(t)) is a composition of differentiable functions and is therefore differentiable at every t ∈ R.
If γ ∈ [tex]C^1(R, R^2)[/tex], which means γ is continuously differentiable, then g ∈ [tex]C^1(R, R)[/tex] as the composition of two continuous functions.
(d) To show that f is
not Fréchet differentiable at the origin (0,0), we need to demonstrate that the formula (Dvf)(0,0) = ⟨∇f(0,0), v⟩ fails for some direction(s) v, where ⟨⋅,⋅⟩ denotes the standard dot product in R².
The gradient of f is given by ∇f = (∂f/∂x, ∂f/∂y). Using the previously derived expressions for the partial derivatives, we have:
∇f(0,0) = (∂f/∂x, ∂f/∂y) = (0, 0)
However, if we take v = (1, 1), the formula (Dvf)(0,0) = ⟨∇f(0,0), v⟩ becomes:
(Dvf)(0,0) = ⟨(0, 0), (1, 1)⟩ = 0
But from part (b), we know that the absolute value of the directional derivative is at most 1. Since (Dvf)(0,0) ≠ 0, the formula fails for the direction v = (1, 1).
Therefore, f is not Fréchet differentiable at the origin (0,0).
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Guys can you please help. I dont understand. Thank you. :))))
Lines AB and CD intersect at E. If the measure of angle AEC=5x-20 and the measure of angle BED=x+50, find, in degrees, the measure of angle CEB.
Answer: 112.5
Step-by-step explanation: When line AB and CD intersect at point E, angle AEC equals BED so you set them equal to each other and find what x is. 5x -20 = x + 50, solving for x, which gives you 17.5. Finding x will tell you what AEC and BED by plugging it in which is 67.5. Angle BED and BEC are supplementary angles which adds up to 180 degrees. So to find angle CEB, subtract 67.5 from 180 and you get 112.5 degrees.
7. Let PN denotes the set of one variable polynomials of degree at most N with real coefficients. Define L : P4 → P³ by L(p(t)) = p'(t) + p"(t). Find the matrix A representing this map under canonical basis of polynomials. And use A to compute L(5 — 2t² + 3t³).
L(5 - 2t² + 3t³) is the polynomial 19 + 18t + 6t².
To find the matrix A representing the map L : P4 → P³ under the canonical basis of polynomials, we need to determine the images of the basis polynomials {1, t, t², t³, t⁴} under L.
1. For the constant polynomial 1, we have:
L(1) = 0 + 0 = 0
This means that the image of 1 under L is the zero polynomial.
2. For the polynomial t, we have:
L(t) = 1 + 0 = 1
The image of t under L is the constant polynomial 1.
3. For the polynomial t², we have:
L(t²) = 2t + 2 = 2t + 2
The image of t² under L is the linear polynomial 2t + 2.
4. For the polynomial t³, we have:
L(t³) = 3t² + 6t = 3t² + 6t
The image of t³ under L is the quadratic polynomial 3t² + 6t.
5. For the polynomial t⁴, we have:
L(t⁴) = 4t³ + 12t² = 4t³ + 12t²
The image of t⁴ under L is the cubic polynomial 4t³ + 12t².
Now we can arrange these images as column vectors to form the matrix A:
A = [0 1 2 3 4
0 0 2 6 12
0 0 0 2 6]
This is a 3x5 matrix representing the linear map L from P4 to P³.
To compute L(5 - 2t² + 3t³) using the matrix A, we write the polynomial as a column vector:
p(t) = [5
0
-2
3
0]
Now we can compute the image of p(t) under L by multiplying the matrix A by the column vector p(t):
L(5 - 2t² + 3t³) = A * p(t)
Performing the matrix multiplication:
L(5 - 2t² + 3t³) = [0 1 2 3 4
0 0 2 6 12
0 0 0 2 6] * [5
0
-2
3
0]
L(5 - 2t² + 3t³) = [0 + 0 + 10 + 9 + 0
0 + 0 + 0 + 18 + 0
0 + 0 + 0 + 6 + 0]
L(5 - 2t² + 3t³) = [19
18
6]
Therefore, L(5 - 2t² + 3t³) is the polynomial 19 + 18t + 6t².
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3. Calculate the Fourier series equation for the equation
0 -2
f(x) = 1 -1
0 1< t <2
The Fourier series equation for the given function f(x) = 1 on the interval 1 < t < 2 is simply f(x) = 0.
To calculate the Fourier series equation for the given function f(x) = 1 on the interval 1 < t < 2, we can follow these steps:
Step 1: Determine the period:
The given interval is 1 < t < 2, which has a length of 1 unit. Since the function is not periodic within this interval, we need to extend it periodically.
Step 2: Extend the function periodically:
We can extend the function f(x) = 1 to be periodic by repeating it outside the interval 1 < t < 2. Let's extend it to the interval -∞ < t < ∞, such that f(x) remains constant at 1 for all values of t.
Step 3: Determine the Fourier coefficients:
To find the Fourier coefficients, we need to calculate the integral of the function multiplied by the corresponding trigonometric functions.
The Fourier coefficient a0 is given by:
a0 = (1/T) * ∫[T] f(t) dt,
where T is the period. Since we have extended the function to be periodic over all t, the period T is infinite.
The integral becomes:
a0 = (1/∞) * ∫[-∞ to ∞] 1 dt = 1/∞ = 0.
The Fourier coefficients an and bn are given by:
an = (2/T) * ∫[T] f(t) * cos(nωt) dt,
bn = (2/T) * ∫[T] f(t) * sin(nωt) dt,
where ω = 2π/T.
Since T is infinite, the integrals become:
an = (2/∞) * ∫[-∞ to ∞] 1 * cos(nωt) dt = 0,
bn = (2/∞) * ∫[-∞ to ∞] 1 * sin(nωt) dt = 0.
Step 4: Write the Fourier series equation:
The Fourier series equation for the given function is:
f(x) = a0/2 + ∑[n=1 to ∞] (an * cos(nωt) + bn * sin(nωt)).
Substituting the Fourier coefficients we calculated, we have:
f(x) = 0/2 + ∑[n=1 to ∞] (0 * cos(nωt) + 0 * sin(nωt)).
Simplifying, we get:
f(x) = 0.
Therefore, the Fourier series equation for the given function f(x) = 1 on the interval 1 < t < 2 is simply f(x) = 0.
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Adventure Airlines
"Welcome to Adventure Airlines!" the flight attendant announces. "We are
currently flying at an altitude of about 10 kilometers, and we are experiencing
technical difficulties.
"But do not panic," says the flight attendant. "Is there anyone here who knows
math? Anyone at all?
You realize that your help is needed, so you grab your trusty graphing
calculator and head to the front of the plane to offer your assistance. "I think
maybe I can help. What's the problem?" you ask.
The flight attendant leads you to the pilot, who is looking a little green and disoriented.
1 am feeling really bad, and I can't think straight," the pilot mumbles.
"What can I do to help?" you ask.
1 need to figure out when to start my descent. How far from the airport should I be if I want to
descend at a 3-angle?" The pilot is looking worse by the second.
"That's easy!" you exclaim. "Let's see. We're at an altitude of 10 km and we want to land on the
runway at a 3-angle. Hmmm.
How far from the airport did you tell the pilot to start his descent?
Answer:
Therefore, the pilot should start the descent approximately 190.84 kilometers from the airport.
Step-by-step explanation:
To determine how far from the airport the pilot should start their descent, we can use trigonometry. The 3-angle mentioned refers to a glide slope, which is the angle at which the aircraft descends towards the runway. Typically, a glide slope of 3 degrees is used for instrument landing systems (ILS) approaches.
To calculate the distance, we need to know the altitude difference between the current altitude and the altitude at which the plane should be when starting the descent. In this case, the altitude difference is 10 kilometers since the current altitude is 10 kilometers, and the plane will descend to ground level for landing.
Using trigonometry, we can apply the tangent function to find the distance:
tangent(angle) = opposite/adjacent
In this case, the opposite side is the altitude difference, and the adjacent side is the distance from the airport where the pilot should start the descent.
tangent(3 degrees) = 10 km / distance
To find the distance, we rearrange the equation:
distance = 10 km / tangent(3 degrees)
Using a calculator, we can evaluate the tangent of 3 degrees, which is approximately 0.0524.
distance = 10 km / 0.0524 ≈ 190.84 km
zach works at the verizon store and wonders if iphones last longer if the screen brightness is set to low. he selects a random sample of 20 brand new iphones from this store and randomly splits them into two groups of 10. for the first group of 10 iphones, he sets the screen brightness to low and then starts a movie. for the second group of 10 iphones, he sets the screen brightness to high and then starts a movie. for each iphone, he measures the amount of time until the battery is all the way dead. he finds that the low brightness iphones lasted longer, on average, than the high brightness iphones.
Based on Zach's random sample of 20 brand new iPhones, it appears that iPhones with low screen brightness lasted longer, on average, compared to iPhones with high screen brightness.
The Zach's experiment, where he randomly split a sample of 20 brand new iPhones into two groups of 10, with one group having low screen brightness and the other group having high screen brightness, and measured the time until the battery was completely depleted, he found that the low brightness iPhones lasted longer, on average, than the high brightness iPhones.
This suggests a correlation between screen brightness and battery life, indicating that setting the screen brightness to low may result in longer battery life for iPhones. However, it's important to note that this experiment is limited in scope and may not represent the overall behavior of all iPhones or guarantee the same results for every individual iPhone.
To draw more conclusive results or make general statements about iPhones' battery life based on screen brightness, further studies and larger sample sizes would be necessary. Additionally, it's worth considering other factors that may affect battery life, such as background processes, usage patterns, battery health, and individual device variations.
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The polynomial of degree 3, P(z), has a root of multiplicity 2 at = 4 and a root of multiplicity 1 at GE 3. The y-intercept is y = - 14.4. Find a formula for P(x). P(x) =
It is given that a polynomial of degree 3, P(z), has a root of multiplicity 2 at z=4 and a root of multiplicity 1 at z=3. The y-intercept is y = -14.4. We need to find the formula for P(x). Let P(x) = ax³ + bx² + cx + d be the required polynomial
Then, P(4) = 0 (given root of multiplicity 2 at z=4)Let P'(4) = 0 (1st derivative of P(z) at z = 4) [because of the multiplicity of 2]Let P(3) = 0 (given root of multiplicity 1 at z=3)P(x) = ax³ + bx² + cx + d -------(1)Now, P(4) = a(4)³ + b(4)² + c(4) + d = 0 .......(2)Differentiating equation (1), we get,P'(x) = 3ax² + 2bx + c -----------(3)Now, P'(4) = 3a(4)² + 2b(4) + c = 0 -----(4)
Again, P(3) = a(3)³ + b(3)² + c(3) + d = 0 ..........(5)Now, P(0) = -14.4Therefore, P(0) = a(0)³ + b(0)² + c(0) + d = -14.4Substituting x = 0 in equation (1), we getd = -14.4Using equations (2), (4) and (5), we can solve for a, b and c by substitution.
Using equation (2),a(4)³ + b(4)² + c(4) + d = 0 => 64a + 16b + 4c - 14.4 = 0 => 16a + 4b + c = 3.6...................(6)Using equation (4),3a(4)² + 2b(4) + c = 0 => 12a + 2b + c = 0 ..............(7)Using equation (5),a(3)³ + b(3)² + c(3) + d = 0 => 27a + 9b + 3c - 14.4 = 0 => 9a + 3b + c = 4.8................(8)Now, equations (6), (7) and (8) can be written as 3 equations in a, b and c as:16a + 4b + c = 3.6..............(9)12a + 2b + c = 0.................(10)9a + 3b + c = 4.8................(11)Subtracting equation (10) from (9),
we get4a + b = 0 => b = -4a..................(12)Subtracting equation (7) from (10), we get9a + b = 0 => b = -9a.................(13)Substituting equation (12) in (13), we geta = 0Hence, b = 0 and substituting a = 0 and b = 0 in equation (9), we get c = -14.4Therefore, the required polynomial isP(x) = ax³ + bx² + cx + dP(x) = 0x³ + 0x² - 14.4, P(x) = x³ - 14.4
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One machine produces 30% of a product for a company. If 10% of
the products from this machine are defective, and the other machines produce no
defective items, what is the probability that an item produced by this company
is defective?
The probability that an item produced by this company is defective is 0.03 or 3%.
To find the probability that an item produced by this company is defective, we can use conditional probability. Let's break down the problem step by step:
Let's assume that the company has only one machine that produces 30% of the products.
Probability of selecting a product from this machine: P(Machine) = 0.3
Probability of a product being defective given it was produced by this machine: P(Defective | Machine) = 0.10
Now, we need to find the probability that any randomly selected item from the company is defective. We can use the law of total probability to calculate it.
Probability of selecting a defective item: P(Defective) = P(Machine) * P(Defective | Machine)
Substituting the values, we get:
P(Defective) = 0.3 * 0.10 = 0.03
Therefore, the probability that an item produced by this company is defective is 0.03 or 3%.
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Problem 5 (Eigenvalues and Eigenvectors). Suppose the vector k 1 is an eigenvector of the matrix A-¹, where the matrix 2 1 1 1 2 1 1 1 2 Compute all possible values of k. A = X=
The possible values of k are ±1.
Step 1: The main answer is that the possible values of k are ±1.
Step 2: To find the possible values of k, we need to consider the eigenvector equation for the matrix A⁻¹. Let's denote the eigenvector as k₁. According to the definition of an eigenvector, we have A⁻¹k₁ = λk₁, where λ represents the eigenvalue corresponding to the eigenvector k₁.
Let's substitute the given matrix A into the equation A⁻¹k₁ = λk₁:
|2 1 1|⁻¹ |k₁₁| = λ |k₁₁|
|1 2 1| |k₁₂| |k₁₂|
|1 1 2| |k₁₃| |k₁₃|
Expanding the equation, we have:
(1/3)k₁₁ + (1/3)k₁₂ + (1/3)k₁₃ = λk₁₁
(1/3)k₁₁ + (1/3)k₁₂ + (1/3)k₁₃ = λk₁₂
(1/3)k₁₁ + (1/3)k₁₂ + (1/3)k₁₃ = λk₁₃
To simplify the equation, we can multiply both sides by 3:
k₁₁ + k₁₂ + k₁₃ = 3λk₁₁
k₁₁ + k₁₂ + k₁₃ = 3λk₁₂
k₁₁ + k₁₂ + k₁₃ = 3λk₁₃
Since k₁ is a non-zero eigenvector, we can divide the above equations by k₁:
1 + (k₁₂/k₁₁) + (k₁₃/k₁₁) = 3λ
(k₁₁/k₁₂) + 1 + (k₁₃/k₁₂) = 3λ
(k₁₁/k₁₃) + (k₁₂/k₁₃) + 1 = 3λ
Let's denote k₁₂/k₁₁ as a, k₁₃/k₁₂ as b, and k₁₁/k₁₃ as c. The above equations become:
1 + a + b = 3λ
c + 1 + b = 3λ
c + a + 1 = 3λ
Adding the three equations, we get:
2(a + b + c) + 3 = 9λ
Since λ is a scalar, it must satisfy the above equation. Simplifying further:
2(a + b + c) = 9λ - 3
2(a + b + c) = 3(3λ - 1)
The right-hand side of the equation is a multiple of 3. Therefore, the left-hand side must also be a multiple of 3. Since a, b, and c are ratios of components of k₁, they can be any real numbers. The only way the left-hand side can be a multiple of 3 is if each of a, b, and c is individually a multiple of 3.
Therefore, the possible values of a, b, and c are all integers. Since they represent ratios of components of k₁, the possible values of k₁ are ±1.
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ep 4. Substitute the equilibrium concentrations into the equilibrium constant expression and solve for x. [H₂][1₂] [HI]² K = (4.16x10-2-x)(6.93×10-2-x) (0.310 + 2x)2 = 1.80x10-² Rearrange to get an expression of the form ax² + bx + c = 0 and use the quadratic formula to solve for x. This gives: X = 9.26x103, 0.134 The second value leads to results that are not physically reasonable.
The values of x obtained from the quadratic formula are x = 9.26x10^3 and x = 0.134. However, the second value of x leads to results that are not physically reasonable.
In the given problem, we are asked to substitute the equilibrium concentrations into the equilibrium constant expression and solve for x. The equilibrium constant expression is given as K = (4.16x10^-2 - x)(6.93x10^-2 - x)/(0.310 + 2x)^2 = 1.80x10^-2.
To solve for x, we rearrange the equation to the form ax^2 + bx + c = 0, where a = 1, b = -2(4.16x10^-2 + 6.93x10^-2), and c = (4.16x10^-2)(6.93x10^-2) - (1.80x10^-2)(0.310)^2.
Using the quadratic formula x = (-b ± √(b^2 - 4ac))/(2a), we substitute the values of a, b, and c to solve for x. This gives two solutions: x = 9.26x10^3 and x = 0.134.
However, the second value of x, 0.134, leads to results that are not physically reasonable. In the context of the problem, x represents a concentration, and concentrations cannot be negative or exceed certain limits. Therefore, the second value of x is not valid in this case.
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Re-write the quadratic function below in Standard Form
y=−(x−1)(x−1)
Answer: y = -x² + 2x - 1
Step-by-step explanation:
y = −(x−1)(x−1) >FOIL first leaving negative in front
y = - (x² - x - x + 1) >Combine like terms
y = - (x² - 2x + 1) >Distribute negative by changing sign of
>everthing in parenthesis
y = -x² + 2x - 1
help asap if you can pls!!!!!
If ∠ABC and ∠DCB form a linear pair, we can conclude that they are supplementary angles (option b) and adjacent angles (option d).
If ∠ABC and ∠DCB are a linear pair, it means that they are adjacent angles formed by two intersecting lines and their non-shared sides form a straight line. Based on this information, we can draw the following conclusions:
a) ∠ABC ≅ ∠DCB: This statement is not necessarily true. A linear pair does not imply that the angles are congruent.
b) ∠ABC and ∠DCB are supplementary: This statement is true. When two angles form a linear pair, their measures add up to 180 degrees, making them supplementary angles.
c) ∠ABC and ∠DCB are complementary: This statement is not true. Complementary angles are pairs of angles that add up to 90 degrees, while a linear pair adds up to 180 degrees.
d) ∠ABC and ∠DCB are adjacent angles: This statement is true. Adjacent angles are angles that share a common vertex and side but have no interior points in common. In this case, ∠ABC and ∠DCB share the common side CB and vertex B.
To summarize, if ∠ABC and ∠DCB form a linear pair, we can conclude that they are supplementary angles (option b) and adjacent angles (option d). It is important to note that a linear pair does not imply congruence (option a) or complementarity (option c).
Option B and D is correct.
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consider the following sets : A = {10, 20, 30, 40, 50} B = {30, 40, 50, 60, 70, 80, 90} What is the value of n(A)?
The value of n(A) is the number of elements in set A. In this case, set A contains five elements, namely 10, 20, 30, 40, and 50. Therefore, the value of n(A) is 5.
The notation n(A) is used to denote the cardinality of set A. The cardinality of a set is the number of distinct elements in the set. For example, if set A contains three elements, then its cardinality is 3.
The cardinality of a set can be determined by counting the number of elements in the set. If a set contains a finite number of elements, then its cardinality is a natural number. If a set contains an infinite number of elements, then its cardinality is an infinite cardinal number.
The concept of cardinality is important in set theory because it allows us to compare the sizes of different sets. For example, if set A has a greater cardinality than set B, then we can say that A is "larger" than B in some sense.
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Find the general solution of the differential equation y" - 81y = -243t + 162t². NOTE: Use t as the independent variable. Use c₁ and cg as arbitrary constants. C1 y(t) =
The general solution to the second order homogenous differential equation is [tex]\(C_1 y(t) = c_1 e^{9t} + c_2 e^{-9t} - 2t^2 + 3t - \frac{4}{81}\)[/tex], where c₁ is a constant multiple of the entire expression.
What is the general solution to the differential equation?To find the general solution of the given differential equation y'' - 81y = -243t + 162t², we can start by finding the complementary solution by solving the associated homogeneous equation y'' - 81y = 0.
The characteristic equation for the homogeneous equation is:
r² - 81 = 0
Factoring the equation:
(r - 9)(r + 9) = 0
This equation has two distinct roots: r = 9 and r = -9
Therefore, the complementary solution is:
[tex]\(y_c(t) = c_1 e^{9t} + c_2 e^{-9t}\)[/tex] where c₁ and c₂ are arbitrary constants
To find a particular solution to the non-homogeneous equation, we can use the method of undetermined coefficients. Since the right-hand side of the equation is a polynomial in t of degree 2, we'll assume a particular solution of the form:
[tex]\(y_p(t) = At^2 + Bt + C\)[/tex]
Substituting this assumed form into the original differential equation, we can determine the values of A, B, and C. Taking the derivatives of [tex]\(y_p(t)\)[/tex]:
[tex]\(y_p'(t) = 2At + B\)\\\(y_p''(t) = 2A\)[/tex]
Plugging these derivatives back into the differential equation:
[tex]\(y_p'' - 81y_p = -243t + 162t^2\)\\\(2A - 81(At^2 + Bt + C) = -243t + 162t^2\)[/tex]
Simplifying the equation:
-81At² - 81Bt - 81C + 2A = -243t + 162t²
Now, equating the coefficients of the terms on both sides:
-81A = 162 (coefficients of t² terms)
-81B = -243 (coefficients of t terms)
-81C + 2A = 0 (constant terms)
From the first equation, we find A = -2.
From the second equation, we find B = 3.
Plugging these values into the third equation, we can solve for C:
-81C + 2(-2) = 0
-81C - 4 = 0
-81C = 4
C = -4/81
Therefore, the particular solution is:
[tex]\(y_p(t) = -2t^2 + 3t - \frac{4}{81}\)[/tex]
The general solution of the differential equation is the sum of the complementary and particular solutions:
[tex]\(y(t) = y_c(t) + y_p(t)\)\(y(t) = c_1 e^{9t} + c_2 e^{-9t} - 2t^2 + 3t - \frac{4}{81}\)[/tex]
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The general solution of the given differential equation is:
y(t) = c₁e^(9t) + c₂e^(-9t) - 2t² + 3t, where c₁ and c₂ are arbitrary constants.
To find the general solution of the given differential equation y" - 81y = -243t + 162t², we can solve it by first finding the complementary function and then a particular solution.
Complementary Function:
Let's find the complementary function by assuming a solution of the form y(t) = e^(rt).
Substituting this into the differential equation, we get:
r²e^(rt) - 81e^(rt) = 0
Factoring out e^(rt), we have:
e^(rt)(r² - 81) = 0
For a nontrivial solution, we require r² - 81 = 0. Solving this quadratic equation, we find two distinct roots: r = 9 and r = -9.
Therefore, the complementary function is given by:
y_c(t) = c₁e^(9t) + c₂e^(-9t), where c₁ and c₂ are arbitrary constants.
Particular Solution:
To find a particular solution, we can assume a polynomial of degree 2 for y(t) due to the right-hand side being a quadratic polynomial.
Let's assume y_p(t) = At² + Bt + C, where A, B, and C are constants to be determined.
Differentiating twice, we find:
y_p'(t) = 2At + B
y_p''(t) = 2A
Substituting these derivatives into the differential equation, we have:
2A - 81(At² + Bt + C) = -243t + 162t²
Comparing coefficients of like powers of t, we get the following equations:
-81A = 162 (coefficient of t²)
-81B = -243 (coefficient of t)
-81C + 2A = 0 (constant term)
Solving these equations, we find A = -2, B = 3, and C = 0.
Therefore, the particular solution is:
y_p(t) = -2t² + 3t
The general solution is the sum of the complementary function and the particular solution:
y(t) = y_c(t) + y_p(t)
= c₁e^(9t) + c₂e^(-9t) - 2t² + 3t
Therefore, the general solution of the given differential equation is:
y(t) = c₁e^(9t) + c₂e^(-9t) - 2t² + 3t, where c₁ and c₂ are arbitrary constants.
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