2/4.7+2/7.10+2/10.13+2/13.16+.....+2/49.52

tính giá trị biểu thức

Answers

Answer 1

It looks like you're trying to evaluate the sum,

[tex]\displaystyle \frac2{4\times7} + \frac2{7\times10} + \frac2{10\times13}+\cdots+\frac2{49\times52}[/tex]

which can be written as

[tex]\displaystyle \sum_{n=1}^{16} \frac2{(3n+1)(3n+4)}[/tex]

Split up the summand into partial fractions:

[tex]\displaystyle \frac2{(3n+1)(3n+4)} = \frac a{3n+1} + \frac b{3n+4} \\\\ \implies 2 = a(3n+4)+b(3n+1) \\\\ \implies 2 = (3a+3b)n+4a+b[/tex]

so that

3a + 3b = 0, or a = -b

4a + b = 2

Solve for a and b :

4a + (-a) = 3a = 2   ==>   a = 2/3   ==>   b = -2/3

So the sum is

[tex]\displaystyle \frac23 \sum_{n=1}^{16} \left(\frac1{3n+1} - \frac1{3n+4}\right)[/tex]

Write out the first terms and observe that several terms cancel with each other:

2/3 (1/4 - 1/7)

+ 2/3 (1/7 - 1/10)

+ 2/3 (1/10 - 1/13)

+ …

+ 2/3 (1/43 - 1/46)

+ 2/3 (1/46 - 1/49)

+ 2/3 (1/49 - 1/52)

So the sum collapses and simplifies to

[tex]\displaystyle \sum_{n=1}^{16} \frac2{(3n+1)(3n+4)} = \frac23 \left(\frac14 - \frac1{52}\right) = \boxed{\frac2{13}}[/tex]


Related Questions

Hey guys ♡
hw r u all doin
pls solve this question for me ⤵️

(m-1)/2 - (m-2)/3 = ( m - 4 )/7 ​

Answers

Answer:

m = - 31

Step-by-step explanation:

Given

[tex]\frac{m-1}{2}[/tex] - [tex]\frac{m-2}{3}[/tex] = [tex]\frac{m-4}{7}[/tex]

Multiply through by 42 , the LCM of 2, 3 and 7 , to clear the fractions

21(m - 1) - 14(m - 2) = 6(m - 4) ← distribute parenthesis

21m - 21 - 14m + 28 = 6m - 24

7m + 7 = 6m - 24 ( subtract 6m from both sides )

m + 7 = - 24 ( subtract 7 from both sides )

m = - 31

solving polinomial(2x+8)(2x-1)​

Answers

Answer:

4x²+14x-8 ( multiplying)

x=-4 , x=1/2 ( find solution)

Step-by-step explanation:

(2x+8)(2x-1)​

start :

2x*2x=4x²

2x*-1 = -2x

8*2x=16x

8*-1=-8

add the results  : 4x²-2x+16x-8 = 4x²+14x-8

If you mean find the solution :

(2x+8)(2x-1)​=0

2x+8=0

x=-8/2=-4

OR 2x-1=0

then x=1/2

Answer:

=4x2+14x−8

Step-by-step explanation:

(2x+8)(2x−1)

=(2x+8)(2x+−1)

=(2x)(2x)+(2x)(−1)+(8)(2x)+(8)(−1)

=4x2−2x+16x−8

=4x2+14x−8

I hope this helps! :]

(x-5)(3x-8)=(4-3x)(6-x)+13​

Answers

Answer:

x = 3

Step-by-step explanation:

Use FOIL method

(x - 5)(3x - 8) = x*3x + x*(-8) + (-5)*(3x) + (-5)*(-8)

                     = 3x² - 8x - 15x + 40        {Combine like terms}

                     = 3x² - 23x + 40

(4 - 3x)( 6 - x) = 4*6 + 4 *(-x) + (-3x)*6 + (-3x)*(-x)

                      = 24  - 4x - 18x + 3x²         {Combine like terms}

                     = 3x² - 22x + 24  

(x - 5)(3x - 8) = (4 - 3x)( 6 - x) + 13

3x² - 23x + 40 = 3x² -22x + 24  + 13

3x² - 23x  + 40 - 3x²  + 22x  - 24 - 13 = 0

3x² - 3x² - 23x + 22x  + 40 - 24 - 13 = 0   {Combine like terms}

0   - x  = 0

 -x +3= 0

         3 = x

x =3

Evaluate ∫4x cos(2-3x)dx

Answers

Answer:

[tex]{ \sf{ \int 4x \cos(2 - 3x) dx = {4x}^{2} \cos(2 - 3x) + c }}[/tex]

Step-by-step explanation:

From integration by parts:

[tex]{ \boxed{ \bf{ \int u \: \frac{dv}{dx} = uv - \int v \: \frac{du}{dx} }}}[/tex]

let u be cos(2-3x) and let dv/dx be 4x:

[tex]{ \sf{ \frac{du}{dx} = 3 \sin(2 - 3x) }} \\ \\ { \sf{ v = \int 4x = 2 {x}^{2} }}[/tex]

Substitute in formular box:

[tex]{ \sf{ = (2 {x}^{2} \times \cos(2 - 3x)) - \int 2 {x}^{2} .3 \sin(2 - 3x) dx}} \\ = { \sf{2 {x}^{2} ( \cos(2 - 3x) - 3 \int \sin(2 - 3x)dx }} \\ { \sf{ = 2 {x}^{2} ( \cos(2 - 3x) - 3( - \frac{1}{3} \cos(2 - 3x) ) + c}} \\ { \sf{ = {4x}^{2} \cos(2 - 3x) + c}}[/tex]

how do you solve 2m-10=44+8m

Answers

Answer:

m = -9

Step-by-step explanation:

2m-10=44+8m

Subtract 2m from each side

2m-2m-10=44+8m-2m

-10 = 44+6m

Subtract 44 from each side

-10-44 = 44-44+6m

-54 = 6m

Divide by 6

-54/6 = 6m/6

-9 = m

Answer:

solve by solving the salvation for equation don't be a slave get educated from what's gave

A taxi charges a flat rate of $8 plus $2 per mile travelled. Write an equation to represent the total cost of a journey. (Let d miles = distance travelled)

Answers

Answer:

Y = 8 + 2d

Step-by-step explanation:

Y = 8 + 2d where d is miles traveled

Answer:

y = 2d + 8

Brainliest, please!

Step-by-step explanation:

y = mx + b

m = slope, b = y-intercept

The flat rate of $8 is the y-intercept, and the slope is $2.

y = 2x + 8

We can change x to d to match the context of this problem.

y = 2d + 8

Find X

A. 3
B. sqrt6
C. 3sqrt3
D. 3sqrt2/2

Answers

Answer:

B. sqrt 6 is the answer.maja

will mark brainliest! determine if this is a one solution, no solution, or infinite solution equation

Answers

No solution. The x’s cancel out which leaves you with ( (1/2) =150). So that is not true which means no solutions

Find the smallest value of $x$ such that $x^2 + 10x + 25 = 8$. [tex]Find the smallest value of $x$ such that $x^2 + 10x + 25 = 8$.[/tex]

Answers

Answer:

[tex]x =-5\ - \sqrt{8}[/tex]

Step-by-step explanation:

Given

[tex]x^2 + 10x + 25 = 8[/tex]

Required

Find the smallest value of x

[tex]x^2 + 10x + 25 = 8[/tex]

Expand the expression on the right hand side

[tex]x^2 + 5x + 5x + 25 = 8[/tex]

Factorize

[tex]x(x+5)+5(x+5) = 8[/tex]

[tex](x+5)(x+5) = 8[/tex]

[tex](x+5)^2 = 8[/tex]

Take Square root of both sides

[tex]\sqrt{(x+5)^2} = \±\sqrt{8}[/tex]

[tex](x+5) = \±\sqrt{8}[/tex]

Remove bracket

[tex]x+5 = \±\sqrt{8}[/tex]

Subtract 5 from both sides

[tex]x+5-5 =-5\± \sqrt{8}[/tex]

[tex]x =-5\± \sqrt{8}[/tex]

[tex]x =-5\ + \sqrt{8}[/tex] or [tex]x =-5\ - \sqrt{8}[/tex]

Comparing both values of x;

The smallest value of x is

[tex]x =-5\ - \sqrt{8}[/tex]

What transformation of the parent function f(x) is made to get f(3x)?

Answers

Answer: Vertically shifting it by 3

The transformation of a function is horizontally shrink by a factor of 3 .

What is a horizontal shrink?We can apply horizontal shrink to a function by multiplying its input values by a scale factor, a, where 0 < 1/a < 1.

Let’s go ahead and look at how f(x) = x2 will be affected by a scale factor of 1/2 and 1/3.

Below is a graph of the data.As we have expected, the graph stretches by a factor of 2 and 3. This is true for all horizontal stretches. The graph only stretches away from the y-axis when we horizontally stretch a graph.Horizontal stretch on other functions will exhibit similar properties. Let’s say we have f(x) = |x|, if this function’s graph is to be stretched horizontally to attain g(x), the new function’s expression can be expressed as |1/3 ∙ x| = |x/3|.

How do you horizontally shrink  by a factor of 3 ?

If g(x) = 3f (x): For any given input, the output of g is three times the output of f, so the graph is stretched vertically by a factor of 3. If g(x) = f (3x): For any given output, the input of g is one-third the input of f, so the graph is shrunk horizontally by a factor of 3.

Learn more about Transformation on :

brainly.com/question/10644134

#SPJ2

The distance between two points on a number line can be found by taking the blank of the blank of the coordinates.

absolute
value
sum
quotient
difference
product

Answers

Answer:

The correct options are;

Absolute value

Difference

Step-by-step explanation:

The distance between two points on a number line can be found by taking the absolute value of the difference  of the coordinates such that the result will always have a positive value

The distance between two, points a and b on the number line is defined as [tex]\left | a - b \right |[/tex] that is the distance is found by taking finding the absolute value of the difference of the two numbers.

PLS HELP ME ON THIS QUESTION I WILL MARK YOU AS BRAINLIEST IF YOU KNOW THE ANSWER PLS GIVE ME A STEP BY STEP EXPLANATION!!
Larry is going on a road trip for work. He is recording how many miles he drives, and how many gallons of gas he uses for his expense report. Which is the independent variable?
A. the amount of gasoline Larry uses
B. the type of car Larry drives
C. the type of roads Larry drives on
D. the amount of miles Larry drives

Answers

Answer: option A the amount of gasoline larry uses

Step-by-step explanation:

This is because a independent variable is not changed by other variables.

please click thanks and mark brainliest if you like :)

Option A: The amount of Gasoline Larry uses. I guess you could say that the dependent variable being (D) is also a Constant Variable because the amount of miles he travels to reach his destination is not changeable. Brainliest plz. Lol


The answer is Option A!

Will Mark Brainlest Help pls​

Answers

Answer:

can you snap it again it's not clear

372 to the nearest 100

Answers

Answer: 400

Explanation: To round 372 to the nearest hundred, we first find the digit in the rounding place which in this case is the 3 in the hundreds place.

To decide whether to round up or down, we look

at the digit to the right of the 3, which is 7.

According to the rules of rounding, if the digit to the right of the

rounding place is greater than or equal to 5, we round up.

So in this problem, since 7 is greater than or equal to 5, we round up.

This means that we add 1 to the 3 in the rounding place

to get 4 and all digits to the right of 4 become 0.

So 372 rounded to the nearest hundred is 400.

Yivgeny's gymnastics scores were 1.5, 1.7, 5.5, and 9.1. In order to calculate his total score, you pick the two top scores and add them. What is his total score?

Answers

Answer:

14.6

Step-by-step explanation:

In the question, we are told that:

Yivgeny's gymnastics scores were 1.5, 1.7, 5.5, and 9.1.

In the question, we are also told that to calculate his total score, we add his top two scores.

Yivgeny's top two gymnastics scores are:

5.5 and 9.1.

Hence, his total scores = 5.5 + 9.1

= 14.6

Yivgeny's total scores = 14.7

Find the product of 0.3×0.23

Answers

Answer:

0.069

Step-by-step explanation:

0.3*0.23=0.069

561
Worksheet
1. Assume that your kidneys can filter out 25% of medicine in your blood every 4 hours. You take one
1000-milligram dose of the medicine. Fill in the table showing the amount of the medicine in your
blood as a function of time. The first three data points are already completed.
At first you will have decimals. Round each value to the nearest milligram so there are no
decimals in your answers.
Time since taking the medicine (in hours)
Amount of medicine in blood (in milligrams)
0
1000
4
1000 - (1000 x 0.25) = 750
8
750 - (750 x 0.25) = 562.5 563
12
16
20
24
28
32
36
40 44 48 52 56

Answers

Answer:

12

563 - (563x0.25) = 422.25 -> 422

16

422 -(422x0.25) = 316.5 -> 317

20

317 - (317x0.25) = 237.75 -> 238

24

238 - (238x0.25) = 178.5 -> 179

28 (continue the step by step process)

134.25 -> 134

32

100.5 -> 101

36

75.75 -> 76

40

57

44

42.75 -> 43

48

32.25 -> 32

52

24

56

18

Step-by-step explanation:

the time interval has to keep skipping by four hours because the medicine is filtered in that amount of time.

The multiplying by 0.25 part must be done first in order to show how much the kidney has filtered.

after this, you need to subtract that from how many milligrams of medicine are left in your system

note that if you do not subtract, you will only be showing how much the kidney has filtered. the question asks for how much is left in the SYSTEM overall, so subtracting is quite necessary to completely answer the question.

I hope this helped.

help me with guys plzzzzz

Answers

Answer:

C

Step-by-step explanation:

So the lion weighs more than the ant right?

And we wish to figure out how much greater the lion's weight is compared to the ant's weight.

So only thing we have to do is divide.

[tex]\frac{1 * 10^5}{2*10^-3} = \frac{10^5}{2*10^-3} = \frac{10^8}{2} = 50000000 = 5 * 10^7[/tex]

Answer:

5×10^7

Step-by-step explanation:

2×10^-3    1×10^5

(1×10^5)/(2×10^-3)=

5×10^7

to scheck :(2*10^-3)(5*10^7)=(1*10^5)

Which of the binomials below is a factor of this trinomial?
X^2 + 5x + 6

Answers

Answer:

(x + 2) , (x + 3) are factors

Step-by-step explanation:

Given

x² + 5x + 6

Consider the factors of the constant term (+ 6) which sum to give the coefficient of the x- term (+ 5)

The factors are + 2  and + 3, since

2 × 3 = 6 and 2 + 3 = 5 , thus

x² + 5x + 6 = (x + 2)(x + 3)

X^2+5x+6=26+15+16 over the time it’s solversd

find the area of parallelogram and round to the nearest tenth.​

Answers

Answer:

A = 152.9 ~ 153

Step-by-step explanation:

A = bh

= 13.9 * 11

= 152.9 ~ 153

Aug 10,9:55:10 AM
Find the length of the third side. If necessary, round to the nearest tenth.
16
10
Submit Answer
Answer:
attempt 1 out of 2

Answers

Answer:

12.5

Step-by-step explanation:

a^2 + b^2 = c^2

a^2 + 10^2 = 16^2

a^2 + 100 = 256

a^2 = 256 - 100

a^2 = 156

a = 12.48 or 12.5

Write a function rule for the table
х
f(x)
0
3
1
4
2
5
3
6

Answers

Answer:

  f(x) = x +3

Step-by-step explanation:

The first differences for adjacent x-values are all 1, so this is a linear function. Because those differences are all 1, it is a linear function with a slope of 1. We observe that f(0) = 3, so that is the y-intercept.

__

The slope-intercept form of a linear function is ...

  y = mx + b . . . . . where m is the slope (1) and b is the y-intercept (3).

A suitable function rule is ...

  f(x) = x +3

For a company picnic, Jacob ordered a box of fresh-baked gingerbread cookies and sugar cookies. The box included a total of 68 cookies, and 75% of them were gingerbread. How many gingerbread cookies did Jacob get?

Answers

Answer:

51 gingerbread cookies

Step-by-step explanation:

Find how many gingerbread cookies he got by finding 75% of 68:

68(0.75)

= 51

So, Jacob got 51 gingerbread cookies.

which is odd one out 4:10 12:25 20:50 8:20​

Answers

Answer:

All of them except 12:25 simply to 2:5. So 12:25 is the odd one out.

Why the answer question now correct

Answers

Answer:

461.58 in²

Step-by-step explanation:

The surface area (A) is calculated as

A = area of base + area of curved surface

   = πr² + πrl ( r is the radius of base and l is slant height )

    = 3.14 × 7² + 3.14 × 7 × 14

    = 3.14 × 49 + 3.14 × 98

    = 3.14(49 + 98)

    = 3.14 ×147

     = 461.58 in²

this graph shows the solution to which inequality (3 3) (-3 -1)

Answers

Answer:

B

Step-by-step explanation:

since the graph shows dotted line the sign has to be < or > so C and D eliminated from your answer

y>2/3 x +1 is your answer (B)

Answer:

[tex] \boxed{y > \frac{2}{3} x + 1}[/tex]

Option B is the correct option.

Step-by-step explanation:

point ₁ ( - 3 , - 1 ) x₁ = - 3 , y₂ = - 1

point ₂ ( 3 , 3 ). x₂ = 3 , y₂= 3

Now, let's find the slope:

Slope ( m ) = [tex] = \frac{y2 - y1}{x2 - x1} [/tex]

[tex] = \frac{3 - ( - 1)}{3 - ( - 3)} [/tex]

[tex] = \frac{3 + 1}{3 + 3} [/tex]

[tex] = \frac{4}{6} [/tex]

[tex] = \frac{2}{3} [/tex]

At ( 3 , - 1 )

y = mx + c , where m is the gradient / slope amd c is called the intercept on y-axis

[tex] - 1 = \frac{2}{3} \times ( - 3) + c[/tex]

Solve for c

[tex] - 1 + 2 = c[/tex]

[tex]c = 1[/tex]

Since, The red line is dotted line. Therefore it does not include the equal to part. And the shaded region is upper part. Hence, ' > ' should be used.

The answer would be:

[tex]y > \frac{2}{3} x + 1[/tex]

Hope I helped!

Best regards!

yesterday the temperature was 1 degree farenheit. today the temperature is 0 degree farhenheit. what is the change in tempeature from yesterday to today

Answers

Answer:

It is one degrees colder

Please please please please help

Answers

Answer:

m = 9

Step-by-step explanation:

8/12 = 6/m

8m = 72

m = 9

Answer:
m=9

Working out:
12÷8=1.5
6x1.5=9

Let me know if you need an explanation.
Hope this helps :)

2x+6y=7draw graph and check x=1,y=2 is solution of this equation​

Answers

Answer:

The solution in the photo

I hope it helps ^_^

Given the equation 4x−8y=32, a second equation that forms a system with no solution is: 1. x−2y=8 2. x−2y=32 3. x+2y=8 4. 2x−y=32

Answers

Answer:

2. x−2y=32.3

Step-by-step explanation:

Given 4x - 8y = 32, a second equation that forms a system with no solution is most easily found by reducing the given equation to x - 2y = 8; we can then easily compare this x - 2y = 8 to x - 2y = 32.3.  These two lines are parallel and thus do not intercept, and thus the system has no solution.

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