Answer: 0.5
Step-by-step explanation:
To find the slope of a line with two given points, you use the formula [tex]m=\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex].
[tex]m=\frac{2-1}{4-2}=\frac{1}{2}=0.5[/tex]
The slope is 0.5.
Find a tangent vector of unit length at the point with the given value of the parameter t. r(t) = 2 sin(t)i + 7 cos(t)j t = π/6
The tangent vector to r(t) at any t in the domain is
[tex]\mathbf T(t)=\dfrac{\mathrm d\mathbf r(t)}{\mathrm dt}=2\cos t\,\mathbf i-7\sin t\,\mathbf j[/tex]
At t = π/6, the tanget vector is
[tex]\mathbf T\left(\dfrac\pi6\right)=\sqrt3\,\mathbf i-\dfrac72\,\mathbf j[/tex]
To get the unit tangent, normalize this vector by dividing it by its magnitude:
[tex]\left\|\mathbf T\left(\dfrac\pi6\right)\right\|=\sqrt{(\sqrt3)^2+\left(-\dfrac72\right)^2}=\dfrac{\sqrt{61}}2[/tex]
So the unit tangent at the given point is
[tex]\dfrac{\mathbf T\left(\frac\pi6\right)}{\left\|\mathbf T\left(\frac\pi6\right)\right\|}=2\sqrt{\dfrac3{61}}\,\mathbf i-\dfrac7{\sqrt{61}}\,\mathbf j[/tex]
Applying derivatives, the tangent vector of unit length at the point given is:
[tex]r_{u}{\prime}(\frac{\pi}{6}) = \frac{2\sqrt{3}}{\sqrt{61}}i - \frac{7}{\sqrt{61}}j[/tex]
The vector function is:
[tex]r(t) = 2\sin{(t)}i + 7\cos{(t)}j[/tex]
The tangent vector is it's derivative, which is given by:
[tex]r^{\prime}(t) = 2\cos{(t)}i - 7\sin{(t)}j[/tex]
At point [tex]t = \frac{\pi}{6}[/tex], we have that:
[tex]r^{\prime}(\frac{\pi}{6}) = 2\cos{(\frac{\pi}{6})}i - 7\sin{(\frac{\pi}{6})}j[/tex]
[tex]r^{\prime}(\frac{\pi}{6}) = \frac{2\sqrt{3}}{2}i - \frac{7}{2}[/tex]
[tex]r^{\prime}(\frac{\pi}{6}) = \sqrt{3}i - \frac{7}{2}[/tex]
The norm of the vector is:
[tex]|r^{\prime}(\frac{\pi}{6})| = \sqrt{\sqrt{3}^2 + (-\frac{7}{2})^2}[/tex]
[tex]|r^{\prime}(\frac{\pi}{6})| = \sqrt{\frac{61}{4}}[/tex]
[tex]|r^{\prime}(\frac{\pi}{6})| = \frac{\sqrt{61}}{2}[/tex]
The unit vector is given by each component divided by the norm, thus:
[tex]r_{u}{\prime}(\frac{\pi}{6}) = \frac{\sqrt{3}}{\frac{\sqrt{61}}{2}}i - \frac{7}{2\frac{\sqrt{61}}{2}}j[/tex]
[tex]r_{u}{\prime}(\frac{\pi}{6}) = \frac{2\sqrt{3}}{\sqrt{61}}i - \frac{7}{\sqrt{61}}j[/tex]
A similar problem is given at https://brainly.com/question/20733439
What is the solution to the inequality below?
x < 5
A. x< 25 or x>-25
B. x < 25 or x>0
O C. x< 25 and x > 0
O D. x < 25 and x>-25
Answer:
C. x < 25 and x ≥ 0
Step-by-step explanation:
Fastest and easiest way to do this is to graph the inequality and find out the lines.
Rafael is saving money to buy a game. So far he has saved $30, which is five-sixths of the total cost of the game. How much does the game cost?
Answer:
$36
Step-by-step explanation:
30 is 5/6 of the game, so we can think that 1/6 is equal to 6, since 5(6) is 30.
If we add another sixth, we get 36, which will be the total cost of the game.
What is the area , rounded to nearest hundredth?
Answer:
57
Step-by-step explanation:
Area of rectangle:
4 x 12
=48
Area of left triangle:
2 x 3 / 2
=3
Area of right triangle:
6 x 2 / 2
=6
Total Area:
48 + 3 + 6 = 57
Answer: 100
Step-by-step explanation: 4 * 12 = 48 6 * 2 / 0.5 = 24 3 * 2 / 0.5 = 12
48+24+12=84 84 to the nearest hundred is 100.
Robert wants to arrange the books for statistics, calculus, geometry, algebra, and trigonometry on a shelf. In how many arrangements can he keep them on the shelf such that the algebra and trigonometry books are not together?
Answer: 72 arrangements
Step-by-step explanation:
The books are:
Statistics, calculus, geometry, algebra, and trigonometry.
So we have 5 books.
We want that algebra and trigonometry are not together.
Suppose that we have 5 positions:
Now, we can start with algebra in the first position.
Now, we have 3 positions for trigonometry (3rd, 4th and 5th).
Now, once those two books are in position, we have 3 other positions and 3 other books, so for the first selection we have 3 options, for the second position we have 2 options, and for the last option we have 1 option.
The number of combinations is equal to the number of options in each selection:
3*(3*2*1) = 18
Now, if Algebra is in the second place, then for trigonometry we have only 2 possible options (4th and 5th)
and for the other 3 books again we have 3*2*1 combinations:
the total number of combinations is:
2*(3*2*1) = 12
If algebra is in the 3rd position, trigonometry has 2 options (1st and 5th)
For the other 3 books, we have 3*2*1 combinations.
The total number of combinations is:
(3*2*1)*2 = 12
in the fourth position is the same as the second position, so here we have again 12 combinations.
For the fifth position is the same as for the first position, so we have 18 combinations.
The total number of combinations is:
C = 18 + 12 +12 +12 +18 = 72
which of the following describes an irrational number?
A. a repeating and non-terminating decimal.
B. a fraction
C. a terminating decimal
D. a non-terminating and non-repeating decimal
Answer:
A.
Step-by-step explanation:
B is wrong because irrational numbers can include pie.
C and D are wrong because irrational numbers don't get a whole number, and instead gives a decimal numbers.
Evauluate 37/100+3/10
Answer:
67/100
Step-by-step explanation:
Find common denominators, note that what you do to the denominator, you must do to the numerator.
The common denominator is 100:
(3/10)(10/10) = (3 * 10)/(10 * 10) = 30/100
Add:
37/100 + 30/100 = 67/100
67/100 is your answer.
~
Answer:
67/100
Step-by-step explanation:
37/100+3/10
Get a common denominator
37/100 + 3/10 *10/10
37/100+30/100
67/100
Given rectangles ABCD and A'B'C'D, describe the transformation that takes place from ABCD to A'B'C'D'
Answer:
A 90° clockwise rotation about the origin and a translation of 7 units down.Step-by-step explanation:
First of all, we need to define the image and pre-image.
The pre-image is the rectangle ABCD, before the transformation. The image is the rectangle A'B'C'D', after the transformation.Second, let's write down the coordinates of each rectangle.
ABCD coordinates:
A(-6,5)
B(-1,5)
C(-1,1)
D(-6,1)
A'B'C'D' coordinates:
A'(5,-1)
B'(5,-6)
C'(1,-6)
D'(1,-1)
The first rule we need to apply is the 90° clockwise rotation which is
[tex](x,y) \implies (y,-x)[/tex]
Which gives us (5,6), (5,1), (1,1), (1,6).
Then, we use the 7 units-down rule
[tex](x,y) \implies (x,y-7)[/tex]
Which gives us (5,-1), (5,-6), (1,-6) and (1,-1).
Therefore, the right answer is the third choice.
Answer:
A 90° clockwise rotation about the origin and a translation of 7 units down.
I need to find for both f(-1) and f(1) it’s
Answer:
f(-1) = -8
f(1) = -12
A copy machine makes 104 copies in 3 minutes and 15 seconds. how many copies does it make per minute
Answer:
32 copiesStep-by-step explanation:
First convert 3 minutes and 15 seconds into minutes by converting 15 sec to min and add it to 3min
60 sec = 1min
15 sec = 15 / 60 × 1 min
= 0.25min
Add it to 3min
3min + 0.25min = 3.25 min
We use ratio and proportion
3.25min = 104 copies
1 min = 104× 1/ 3.25
= 104 / 3.25
= 32
The final answer is 32 copies
Hope this helps you.
Answer:
Step-by-step explanation:
3 min 15 sec = 3*60 + 15 = 180 + 15 = 195 seconds
In 195 seconds 104 copies are made
In one second, the number of copies made = [tex]\frac{104}{195}\\[/tex]
In 60 seconds, the number of copies made = [tex]\frac{104}{195}*60[/tex]
= 32 copies
The polynomial 24x3 − 54x2 + 44x − 99 is factored by grouping. 24x3 − 54x2 + 44x − 99 24x3 + 44x − 54x2 − 99 4x(____) − 9(____) What is the common factor that is missing from both sets of parentheses? 6x + 11 6x − 11 6x2 + 11 6x2 − 11
Answer: 6x² + 11
Step-by-step explanation:
24x³ - 54x² + 44x - 99
= 6x²(4x - 9) + 11(4x - 9)
= (6x² + 11) (4x - 9)
This can be rewritten as: 4x(6x² + 11) - 9(6x² + 11)
This is the answer to your problem.
For a segment of a radio show a disc jockey can play 10 records. If there are 12 records to select from in how many ways can the program for this segment be arranged
Answer:
66 different waysStep-by-step explanation:
This is a combination question. Combination has to do with selection. For example if r objects are to be selected from n pool of oblects, this can be done in nCr number of ways.
nCr = n!/(n-r)r!
According to the question, if a radio show can only play 10 records out of 12 records available, this can be done in 12C10 number of ways.
12C10 = 12!/(12-10)!10!
= 12!/2!10!
= 12*11*10!/2*10!
= 12*11/2
= 6*11
= 66 different ways
the sum of the first 20 terms of an A.P is identical to the sum of the first 22 term.If the common difference is -2; find the first terms
Answer:
First term a = 41
Step-by-step explanation:
Arithmetic Progression:
Common differences d = -2
[tex]S_{n}=\frac{n}{2}(2a+[n-1]d)\\\\S_{20}=\frac{20}{2}(2a+19*[-2])\\\\[/tex]
= 10*(2a - 38)
= 10*2a - 10*38
=20a - 380
[tex]S_{22}=\frac{22}{2}(2a+21*[-2])\\\\[/tex]
= 11 (2a -42)
=11*2a - 11*42
= 22a - 462
[tex]S_{22}=S_{20}\\\\[/tex]
22a - 462 = 20a - 380
22a = 20a - 380 + 462
22a = 20a + 82
22a - 20a = 82
2a = 82
a = 82/2
a = 41
First term a = 41
how do you graph y=–7/3x+2. PLEASE HELP ME
Graph the line using the slope and y-intercept, or two points.
Slope: -7/3
y-intercept: 2
Please mark me as brainliest if possible. Stay safe and God bless you!!
<3
- Eli
What is the simple interest earned on
$300 over 6 years at 4% interest?
Answer:
$72
Step-by-step explanation:
I = Prt
I = ($300)(0.04)(6)
I = $72
Which of the following illustrates the truth value of the following mathematical statements?
6 + 3 = 9, and 5.5 = 20
Answer: 6 + 3 = 9
Step-by-step explanation:
5.5 does not equal to 20
An item has a listed price of $30 if the sales tax rate is 7% how much is the sales tax in dollars
Answer:
The sales tax is 2.10
Step-by-step explanation:
Take the price of the item and multiply by the sales tax rate to determine the tax
30 * 7%
30 * .07
2.10
The sales tax is 2.10
A baseball card collector buys and opens 360 packs of 1989 Fleer baseball cards. He is told that there is a 2.3% chance of anyone pack containing the coveted Billy Ripken error card. Find the mean and standard deviation of the random variable "number of Billy Ripken error cards ound", where n-360
Answer:
Mean: 8.28
Standard deviation: 2.84
Step-by-step explanation:
This random variable "number of Billy Ripken error cards found" can be described by the binomial distribution, with sample size n=360 (number of packs) and probability of success p=0.023 (probabillity of a pack containing the coveted Billy Ripken error card).
Then, the mean and standard deviation are calculate as for the binomial distribution:
[tex]\mu=np=360\cdot 0.023=8.28\\\\\sigma=\sqrt{np(1-p)}=\sqrt{360\cdot 0.023\cdot 0.977}=\sqrt{8.08956}\approx2.84[/tex]
A ball is thrown vertically upward from the ground. Its distance in feet from the ground in t seconds is s equals negative 16 t squared plus 256 t. After how many seconds will the ball be 1008 feet from the ground?
Answer:
7 seconds
Step-by-step explanation:
Given the height equation of the motion;
s = -16t^2 + 256t
At s = 1008 ft
The equation becomes;
1008 = -16t^2 + 256t
16t^2 - 256t + 1008 = 0
Solving the quadratic equation for t;
Factorising, we have;
16(t-7)(t-9) = 0
t = 7 or t = 9
When the ball is going up it would reach the given height at time t = 7 seconds.
When it is coming down it would reach the given height at time t = 9 seconds.
The probability that a grader will make a marking error on any particular question of a multiple-choice exam is 0.10. If there are ten questions and questions are marked independently, what is the probability that no errors are made
Answer:
0.9^10
Step-by-step explanation:
The probability to make an error in 1 question =0.1 => The probability that this one particular question will be answered correctly is P=1-0.1=0.9
There are 10 questions that are independent from each other .
The probability to be answered correctly is 0.9 each. So the probability to answer correctly to all of them is
P(10quest=correct) =0.9*0.9*0.9*0.9*0.9*0.9*0.9*0.9*0.9*0.9=0.9^10
toilet rolls come in packs of 4 and 9
the 4 packed price $2.04
and the 9 packed is priced at $4.68
Answer: 2.04÷ 4= 0.51
4.68÷9= 0.52
4 pack is better value by 0.01
The sum of an irrational number and a rational number is irrational. Sometimes True Always True Never True
Answer:
Always true
Step-by-step explanation:
Trust me
Answer:
true
Step-by-step explanation:
which linear is represented by the graph?
3. A strip of wood 78 inches long is to be cut into pieces 3 3la inches long. How many pieces can be cut?
A. 21
B. 12
C. 26
D.20
Answer:
Option D (20) is the right answer.
Step-by-step explanation:
The given values are:
Length of wood,
= 78 inches
Wood pieces,
= [tex]3\frac{3}{4} \ inches[/tex]
On converting this in proper fraction, we get
= [tex]3\frac{3}{4}[/tex]
= [tex]\frac{15}{4}[/tex]
= [tex]3.75 \ inches[/tex]
Now,
On dividing "78" from "3.78", we get
= [tex]\frac{78}{3.75}[/tex]
= [tex]20.8 \ pieces[/tex]
So we got "20 pieces".
Which lines are parallel? Justify your answer.
A. Lines a and b are pa because their corresponding angles are congruent.
B. Lines a and b are parallel because their same side exterior angles are congruent.
C. Lines e and f are parallel because their corresponding angles are congruent.
D. Lines e and f are parallel because their same side exterior angles are supplementary.
Answer:
A. Lines a and b are pa because their corresponding angles are congruent.
Step-by-step explanation:
The corresponding angles are both 110 degrees.
To determine if a particular predictor in a regression analysis is statistically significant, which statistic should one interpret
Answer:
The test statistic used to determine whether a particular predictor in a regression analysis is statistically significant is:
[tex]t=\frac{\beta_{i}}{S.E._{\beta_{i}}}[/tex]
Step-by-step explanation:
The general form of a regression equation is:
[tex]y=\alpha +\beta_{1}x_{1}+\beta_{2}x_{2}+...+\beta_{n}x_{n}[/tex]
Here,
α = y-intercept
βi = regression coefficients, (i = 1, 2, ..., n)
A regression analysis is performed to determine whether the predictor variables are statistically significant or not.
The output of the regression analysis consists of two tables.
One is the regression output and the other is the ANOVA table.
The regression output table is used to display which predictor variables are statistically significant and which are not.
The test statistic used to determine whether a particular predictor in a regression analysis is statistically significant is:
[tex]t=\frac{\beta_{i}}{S.E._{\beta_{i}}}[/tex]
And the ANOVA table displays overall regression analysis.
The F-test statistic is used to for the overall regression analysis.
Thus, the test statistic used to determine whether a particular predictor in a regression analysis is statistically significant is:
[tex]t=\frac{\beta_{i}}{S.E._{\beta_{i}}}[/tex]
P(x)⋅Q(x)=R(x); if P(x)=x+2 and R(x)=x3−2x2−6x+4, what is Q(x)?
Answer: Q(x) = x² - 4x + 2
Step-by-step explanation:
P(x) · Q(x) = R(x) ⇒ Q(x) = R(x)/P(x)
R(x) = x³ - 2x² - 6x + 4 ÷ P(x) = x + 2
I will use synthetic division (but you can also use long division).
-2 | 1 -2 -6 4
| ↓ -2 8 -4
1 -4 2 0 ← remainder
The reduced polynomial is: x² - 4x + 2
In a fish tank the number of orange fish is 1 1/4 times the number of blue fish. Drag the blue fish to represent the number of blue fish in the tank dor every 5 orange fish
Answer:
4 blue fish for every 5 orange fish
Step-by-step explanation:
(orange fish) = (1 1/4)·(blue fish) . . . . . the given relation
(orange fish) = (5/4)·(blue fish) . . . . . write as improper fraction
(orange fish)/(blue fish) = 5/4 . . . . . divide by "blue fish"
There are 4 blue fish for every 5 orange fish.
Jensen Tire & Auto is in the process of deciding whether to purchase a maintenance contract for its new computer wheel alignment and balancing machine. Managers feel that maintenance expense should be related to usage, and they collected the following information on weekly usage (hours) and annual maintenance expense (in hundreds of dollars).
Weekly Usage
(hours) Annual Maintenance
Expense ($100s)
13 17.0
10 22.0
20 30.0
28 37.0
32 47.0
17 30.5
24 32.5
31 39.0
40 51.5
38
40.0
(a) Use the data to develop an estimated regression equation that could be used to predict the annual maintenance expense for a given number of hours of weekly usage. What is the estimated regression model?
Let x represent the number of hours of weekly usage.
If required, round your answers to two decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300)
(b) Test whether each of the regression parameters β0 and β1 is equal to zero at a 0.05 level of significance. What are the correct interpretations of the estimated regression parameters? Are these interpretations reasonable?
(c) How much of the variation in the sample values of annual maintenance cost does the model you estimated in part (b) explain?
If required, round your answer to two decimal places.
(d) If the maintenance contract costs $3000 per year, would you recommend purchasing it? Explain.
Answer:
Step-by-step explanation:
Hello!
The given data corresponds to the variables
Y: Annual Maintenance Expense ($100s)
X: Weekly Usage (hours)
n= 10
∑X= 253; ∑X²= 7347; [tex]\frac{}{X}[/tex]= ∑X/n= 253/10= 25.3 Hours
∑Y= 346.50; ∑Y²= 13010.75; [tex]\frac{}{Y}[/tex]= ∑Y/n= 346.50/10= 34.65 $100s
∑XY= 9668.5
a)
To estimate the slope and y-intercept you have to apply the following formulas:
[tex]b= \frac{sumXY-\frac{(sumX)(sumY)}{n} }{sumX^2-\frac{(sumX)^2}{n} } = \frac{9668.5-\frac{253*346.5}{10} }{7347-\frac{(253)^2}{10} }= 0.95[/tex]
[tex]a= \frac{}{Y} -b\frac{}{X} = 34.65-0.95*25.3= 10.53[/tex]
^Y= a + bX
^Y= 10.53 + 0.95X
b)
H₀: β = 0
H₁: β ≠ 0
α:0.05
[tex]F= \frac{MS_{Reg}}{MS_{Error}} ~~F_{Df_{Reg}; Df_{Error}}[/tex]
F= 47.62
p-value: 0.0001
To decide using the p-value you have to compare it against the level of significance:
If p-value ≤ α, reject the null hypothesis.
If p-value > α, do not reject the null hypothesis.
The decision is to reject the null hypothesis.
At a 5% significance level you can conclude that the average annual maintenance expense of the computer wheel alignment and balancing machine is modified when the weekly usage increases one hour.
b= 0.95 $100s/hours is the variation of the estimated average annual maintenance expense of the computer wheel alignment and balancing machine is modified when the weekly usage increases one hour.
a= 10.53 $ 100s is the value of the average annual maintenance expense of the computer wheel alignment and balancing machine when the weekly usage is zero.
c)
The value that determines the % of the variability of the dependent variable that is explained by the response variable is the coefficient of determination. You can calculate it manually using the formula:
[tex]R^2 = \frac{b^2[sumX^2-\frac{(sumX)^2}{n} ]}{[sumY^2-\frac{(sumY)^2}{n} ]} = \frac{0.95^2[7347-\frac{(253)^2}{10} ]}{[13010.75-\frac{(346.50)^2}{10} ]} = 0.86[/tex]
This means that 86% of the variability of the annual maintenance expense of the computer wheel alignment and balancing machine is explained by the weekly usage under the estimated model ^Y= 10.53 + 0.95X
d)
Without usage, you'd expect the annual maintenance expense to be $1053
If used 100 hours weekly the expected maintenance expense will be 10.53+0.95*100= 105.53 $100s⇒ $10553
If used 1000 hours weekly the expected maintenance expense will be $96053
It is recommendable to purchase the contract only if the weekly usage of the computer is greater than 100 hours weekly.
he data show the bug chirps per minute at different temperatures. Find the regression equation, letting the first variable be the independent (x) variable. Find the best predicted temperature for a time when a bug is chirping at the rate of 3000 chirps per minute. Use a significance level of 0.05. What is wrong with this predicted value?
Answer:
^Y= 26.72 + 0.0547Xi
^Y/[tex]_{X=3000}[/tex]= 190.82ºF
B. It is unrealistically high.
Step-by-step explanation:
Hello!
*Full text*
The data show the bug chirps per minute at different temperatures. Find the regression equation, letting the first variable be the independent (x) variable. Find the best predicted temperature for a time when a bug is chirping at the rate of 3000 chirps per minute. Use a significance level of .05. What is wrong with this predicted value?
Chirps in 1 min. 929 854 771 1004 1201 1027
Temperature (F) 81.3 77.3 64.8 80.3 92.2 80.9
What is the regression equation?
^y= _____ + _____
(Round the x-coefficient to four decimal places as needed. Round the constant to two decimals as needed)
What is the predicted value? ^y= _____ (Round to one decimal places as needed)
What is wrong with this predicted value?
A. The first variable should have been the dependent variable
B. It is unrealistically high.
C. It is only an approximation
D. Nothing is wrong with this value
To calculate the regression equation you have to estimate the slope and the y-intercept.
^Y= a + bX
Estimate of the slope:
[tex]b= \frac{sumXY-\frac{(sumX)(sumY)}{n} }{sumX^2-\frac{(sumX)^2}{n} }[/tex]
n= 6
∑X= 5786 ∑X²= 5691944 [tex]\frac{}{X}[/tex]= 964.33
∑Y= 476.80 ∑Y²= 38277.76 [tex]\frac{}{Y}[/tex]= 79.47
∑XY= 465940.4
[tex]b= \frac{465940.4-\frac{5786*476.80}{6} }{5691944-\frac{(5786)^2}{6} }= 0.0547[/tex]
Estimate of the Y-intercept:
[tex]a= \frac{}{Y} -b*\frac{}{X}[/tex]
[tex]a= 79.47 -0.0547*964.33= 26.696= 26.72[/tex]
The estimated regression equation is:
^Y= 26.72 + 0.0547Xi
^Y/[tex]_{X=3000}[/tex]= 26.72 + 0.0547*3000= 190.82ºF
At the rate of 3000 chirps per minute it is expected a temperature of 190.82ºF
As you can see it is unrealistic to think that the chirping rate of bugs will have any effect over the temperature. For what is known about bugs, they tend to be more active to higher temperatures.
Considering the value obtained, as it is incredible high, if this regression was correct, every time the chirping rate of bugs increases, the ambient temperature would rise to levels incompatible with life.
I hope this helps!