Given the curve [tex]\displaystyle \large{y=e^{-x}\sin x \ \ (x\geq 0)[/tex] let the area enclosed by the curve and the x-axis (above the x-axis) be S0, S1, S2, ... , Sn, ... in order from y-axis. Find [tex]\displaystyle \large{ \lim_{n \to \infty} \sum_{k=0}^{n} S_k}[/tex]

Answers

Answer 1

The given curve crosses the x-axis whenever x is a multiple of π, and it lies above the x-axis between consecutive even and odd multiples of π. So the regions with area S₀, S₁, S₂, ... are the sets

[tex]R_0 = \left\{(x, y) : 0 \le x \le \pi \text{ and } 0 \le y \le e^{-x}\sin(x)\right\}[/tex]

[tex]R_1 = \left\{(x, y) : 2\pi \le x \le 3\pi \text{ and } 0 \le y \le e^{-x}\sin(x)\right\}[/tex]

[tex]R_2 = \left\{(x, y) : 4\pi \le x \le 5\pi \text{ and } 0 \le y \le e^{-x}\sin(x)\right\}[/tex]

and so on, with

[tex]R_k = \left\{(x, y) : 2k\pi \le x \le (2k+1)\pi \text{ and } 0 \le y \le e^{-x}\sin(x)\right\}[/tex]

for natural number k.

The areas themselves are then given by the integral

[tex]S_k = \displaystyle \int_{2k\pi}^{(2k+1)\pi} \int_0^{e^{-x}\sin(x)} dy \, dx = \int_{2k\pi}^{(2k+1)\pi} e^{-x}\sin(x) \, dx[/tex]

Integrate by parts twice. Take

[tex]u = e^{-x} \implies du = -e^{-x} \, dx[/tex]

[tex]dv = \sin(x) \, dx \implies v = -\cos(x)[/tex]

so that

[tex]\displaystyle \int e^{-x}\sin(x) \, dx = -e^{-x}\cos(x) - \int e^{-x}\cos(x) \, dx[/tex]

then

[tex]u = e^{-x} \implies du = -e^{-x} \, dx[/tex]

[tex]dv = \cos(x) \, dx \implies v = \sin(x)[/tex]

so that

[tex]\displaystyle \int e^{-x}\cos(x) \, dx = e^{-x}\sin(x) + \int e^{-x}\sin(x) \, dx[/tex]

Overall, we find

[tex]\displaystyle \int e^{-x}\sin(x) \, dx = -e^{-x}\cos(x) - e^{-x}\sin(x) - \int e^{-x}\sin(x) \, dx[/tex]

or

[tex]\displaystyle \int e^{-x}\sin(x) \, dx = -\frac12 e^{-x} (\cos(x)+\sin(x)) + C[/tex]

Using the antiderivative and the fundamental theorem of calculus, we compute the k-th area to be

[tex]\displaystyle S_k = -\frac12 e^{-(2k+1)\pi} (\cos((2k+1)\pi)+\sin((2k+1)\pi)) + \frac12 e^{-2k\pi} (\cos(2k\pi)+\sin(2k\pi))[/tex]

[tex]\displaystyle S_k = \frac12 e^{-2k\pi} \cos(2k\pi) \left(e^{-\pi} + 1\right)[/tex]

[tex]\displaystyle S_k = \frac{e^{-\pi}+1}2 e^{-2k\pi}[/tex]

Since [tex]\left|e^{-2\pi}\right|<1[/tex], the sum we want is a convergent geometric sum. As n goes to ∞, we have

[tex]\displaystyle \lim_{n\to\infty} \sum_{k=0}^n S_k = \frac{e^{-\pi}+1}2 \cdot \frac1{1 - e^{-2\pi}} = \boxed{\frac{e^\pi+1}{4\sinh(\pi)}}[/tex]


Related Questions

Solve.

x2=−0.73

What is the solution to the equation?

Enter your answer as a decimal in the box.

x =

Answers

x = -0.365 (If its x(2)=-0.73)

How I solved it:

x^2=-0.73

-0.73÷2=-0.365

//

-0.365×2=-0.73

Therefore, the answer is -0.365.

Answer:

x = -1.46 (if its x/2=-0.73)

x/2=-0.73

-0.73x2=-1.46

therefore,

-1.46/2=-0.73

///

making the answer

-1.46

What is the value of the expression Negative 225 divided b (negative 15)?
What is the value of the expression 30 divided by (negative 6)?

Answers

Answer:

-15-5

Step-by-step explanation:

What is the value of the expression Negative 225 divided b (negative 15)?

What is the value of the expression 30 divided by (negative 6)?

I answer for what I understand

-225 : 15 = - 15

30 : (- 6 ) = -5

What will be the result when each term sin2theta+cos2theta =1 is divided by sin2theta

Answers

Answer: Did you copy and paste this because this just hits different. message me if i misunderstood this.

Step-by-step explanation:

Find the area of a trapezoid with height h and bases b1 and b2.

h=6 in.

b1=9 in.

b2=11 in.

Answers

The answer is the following

9+11 = 20
20/2 = 10
10 x 6 = 60

what is 9 less than 3 times f

Answers

It is 3f - 9

So you multiply f by 3 and subtract 9
As simple as that!

the length of 2x metres and it's width is 2 metres shorter than its length. what is the area of the rectangle​

Answers

Answer:

4x^2-4x

Step-by-step explanation:

2x*(2x-2)

(2x)(2x)+(2x)(−2)

[tex]4x^2-4x[/tex]

Hope this helped! :)

aaaaaaaaaaaaaaaaaaaa

Answers

Answer:

what grade are you??..........

Use long division to find the quotient below. (8x^3-10x^2-19x-15)/(2x-5)

Answers

Answer:

4x2 + 5x + 3

Step-by-step explanation:

Brendan says that the negative of - 1/3
is 3 because they are on ​opposite sides of zero when they are plotted on the number line.

​Is Brendan correct? Explain your answer.

Answers

Answer:

No! Brendan has totally got the wrong idea.

Step-by-step explanation:

Numbers on the right hand side of zero are said to be positive, while, the numbers on the opposite side are said to be negative.

That means Brendan's correct in saying that -1/3 lies on the opposite side of 3, since negative numbers lie on the opposite side of the positives.

But,

Negative "of" a number is the same number with opposite sign.

That is, if a number is 3 units away from the zero, it's negative will also be 3 units away from zero, but on the opposite side.

-1/3 and 3 do not lie at the same distance from zero.

-1/3 would be approached before -1 by walking in the negative direction whereas 3 would be approached after 1.

Therefore, Brendan is wrong as the negative of a number has opposite sign but same "magnitude".

find the equation of the line with slope of 2 passing through (3,1)

Answers

Answer:

y = 2x - 5

Step-by-step explanation:

Find the product z1z2 in standard form. (Simplify your answer completely.)
z1 = 9 + 3i, z2 = −9 + 3i

Answers

Answer:

See image

Step-by-step explanation:

These are "complex numbers" because they have the imaginary number, i, in the expression.

The 9 (and the -9) is the real part and the 3i is the imaginary part. But when you add or subtract, multiply or divide them you can manipulate them just as if the i was a variable (like x or n or y) If you learned to multiply

(x+2)(x+5)

= x^2 + 7x + 10

This problem will work the same way. You may have learned "FOIL" or using a box to multiply two binomials (two-piece things like x+2)

**SUPER IMPORTANT NOTE: i^2 is equal to -1

These particular complex numbers are called conjugates which means they have the same 'pieces' the 9 and the 3i, with only one sign different. So there is a short cut for this problem and the imaginary number falls out and we get a real number answer. This doesn't happen for every question, only when you multiply conjugates, but the method shown here works for multiplying complex numbers all the time.

FLOORING Miguel is putting hardwood flooring in a hallway that measures 4 feet by 17 feet. The wood he has chosen is $5.48 per square foot

What is the range of the actual cost of putting the flooring in the hallway?

OA) $316.47 and $372.64

OB) $372.64 and $431.55

O C) $362.64 and $382.64

OD) $316.47 and $431.55

Answers

A I think yup it's A good luck

Step-by-step explanation:

Miguel is putting hardwood flooring in a hallway that measures 4 feet by 17 feet. The wood he has chosen is $5.48 per square foot

What is the range of the actual cost of putting the flooring in the hallway?

OA) $316.47 and $372.64

OB) $372.64 and $431.55

O C) $362.64 and $382.64

OD) $316.47 and $431.55

my Christmas present to you​

Answers

Answer:

super man

Step-by-step explanation:

please help me with math

Answers

Hi there! :)

5-2b when b=-1; 3.

5-2(-1)

5+2

7

5-2(3)

5-6

-1

3(x+8)

3x+24

Hope it helps!

~Answer given by

An Unknown Dreamer

Good luck.

Calculate the frequency of a wave with a speed of 130 m/s and a wavelength of 2.5

Answers

Answer:

  52 Hz

Step-by-step explanation:

We can divide the speed by the wavelength to find the number of waves propagated in one second:

  (130 m/s)/(2.5 m/wave) = 52 waves/s

The SI unit of frequency is the Hertz, equal to one cycle per second.

The frequency of this wave is 52 Hz.

_____

Additional comment

The use of the unit Hz to signify frequency was adopted in 1933, but did not replace the unit "cycles per second" (CPS) until a number of years later.

find the side of square whose perimeter. is 24.8cm.​

Answers

Answer:

6.2

Step-by-step explanation:

What inequality is represented by this graph?
O X > 6 O X _< 6 O X<6 OX_>6

Answers

last option in the picture

Hey y’all,please help me :)

Answers

Answer:

-c-4≥8

Step-by-step explanation:

Just ask!

Hope this helps. :)

Solve the following system of equations.

2x + y=3
x=2y-1

Make sure there are NO SPACES in your answer. Include a comma in your answer.

ANSWER: {(
)}

Answers

Answer:

x=1,y=1

Step-by-step explanation:

For this problem, we can use the substitution method. Since we know that x is equal to 2y-1, we can rewrite the first equation as 2(2y-1)+y=3. Now solving we get:

4y-2+y=3

5y-2=3

5y=5

y=1

Now we can plug in 1 for y in the second equation and get:

x=2(1)-1

x=1

This means that x=1, and y=1

Simply using quadratic formula! Brainliest will be awarded if correct

Answers

Answer:

[tex]\left \{ {{y1=-1.2+0.4i} \atop {y2=-1.2-0.4i}} \right.[/tex]

Step-by-step explanation:

5y + 12 = [tex]\frac{-8}{y}[/tex]

y*(5y+12)=-8

5[tex]y^{2}[/tex] + 12y = -8

5[tex]y^{2}[/tex] + 12y + 8 = 0

Δ(Delta) = [tex]b^{2}[/tex] - 4ac

= [tex]12^{2}[/tex] - 4*5*8

= -16

Δ<0

therefore we have complex number

y = [tex]\frac{-b}{2a}[/tex] ± [tex]\frac{\sqrt{|Delta|} }{2a}[/tex]

[tex]\left \{ {{y1=-1.2+0.4i} \atop {y2=-1.2-0.4i}} \right.[/tex]

if ur good at math, pls help. will get brainliest

Answers

Answer: y = -x - 3

Using the parent function/formula y = mx +b, you can use the slope formula [tex]\frac{x_{2}-x_1 }{y_2-y_1}[/tex] to determine that the slope is negative. Then, using the answer to the slope equation (m), you can use 2 points from the table to solve the equation for b. Then just write the equation using y, x, value of m, and value of b.

Write the following equation in standard form:`X^{2}+6X=-2`

Answers

Answer:

[tex]x^2 +6x +2=0[/tex]

Step-by-step explanation:

Problem #3
Imagine you are building a triangular garden. Two sides of the garden measure 230 ft and
360 ft and the included angle between these two sides of the garden measures 38°. What is
the measure of the third side?
С
230ft
38
360ft

Answers

Answer:

b = 115.4 feet

Step-by-step explanation:

b^2 = a^2 + c^2 - 2 (a)(b) x cos B

b^2 = 230^2 + 360^2 - 2(230)(360) x cos(38 degrees)

b^2 = 52,900 + 129,600 - 2(230)(360) x cos(38 degrees)

b^2 = 182,500 - 165,600 x cos(38 degrees)

b = [tex]\sqrt{(16,900)(cos(38)) }[/tex]

b = 115.4 feet

i hope this helps!! :)

Answer:

115.4 ft

Step-by-step explanation:

Given the function f(x) = x2 - x + 7, find each of the following.
f(6)=
f(- 9)=
f(0)

Answers

Answer:

37, 79, 7

Step-by-step explanation:

f(6) = 6² -6 +7

36-6+7 is 37

f(-9) = -9² -9+7

81-9+7 is 79

f(0) = 0² -0+7

0-0+7 is 7

What function equation is represented by the graph?

Answers

Answer:

f(x) = (2/3)x-2

Step-by-step explanation:

Pick any two points and calculate the slope.  I chose:  (-3,-4) and (3,0).  The Rise/Run, or slope, is (0-(-4))/(3-(-3) or 4/6:  2/3

The y-intercept of the graph is -2 ( the value of y when x=0).

Given y = mx + b

we have

y = (2/3)x - 2

Option 3

Tommy bought one dozen donuts. He gave one-sixth of the donuts to his wife. He then gave one-fifth of the remaining donuts to his son. He took the rest to work. How many donuts did Tommy take to work?

Answers

Answer:

8

Step-by-step explanation:

1/6 of 12 is 2

12 - 2 = 10

1/5 of 10 is also 2

10 - 2 = 8

Tommy took 8 donuts to work.

please help asap!!!!

Answers

Answer:

justin biberis black

Step-by-step explanation:

Help me pls imma fail

Answers

Answer:

-

Step-by-step explanation:

Plot /\ABC: B(-1,-1), and C(4,-1)
——JUST LOOK AT PHOTO AND PLEASE HELP

Answers

Answer:

i dont know sry

Step-by-step explanation:

:)

Can someone plss help me with this!!!

Answers

Answer:

10/1 or 10

Step-by-step ex planation:

The rate of change is just a fancy word for slope!

To find the slope of this line I found two points of the graph that were easy to determine.  Slope = rise/run

which is this case was rise 10 because the point went from 20 to 30 and the run being 1 because it was going from 1 to 2

Hope this helps!!

Please tell me if I have messed up!!

I enjoy learning from my mistakes:)

Other Questions
pleaseeee help?????? I heard there is going to be a new Harry Potter movie!!!!! the squirrel reached for the bird feeder for he saw an abundance of sunflower seeds What do you think was the long-term impact of the Great Western Schism on the Catholic Church? (please don't search for the first thing on go0gle, I already saw it and didn't have enough information) Bob is an 80-year-old man who demonstrates a typical pattern of performance on intelligence measures for someone at his developmental stage. Which measure of intelligence is Bob most likely to perform better on now than when he was 30 years old need help asap!!!!i can encourage my classmates to stay on task with their school work by..(finish the sentence) i really need help on this HELP ! Will give brainliest Last year, a gardening store ordered 8,910 potted plants. This year, they ordered 9,801 potted plants. What is the percent of increase in the number of potted plants ordered annually? A system of linear equations includes the line that is created by the equation Y = 0.5x-1 and the line through thepoints (3, 1) and (-5, -7), shown below.What is the solution to the system of equations?A. (-6, -4)B. (0, -1)C. (0, -2)D. (2, 0) estimate the area of the following irregular shapes will give brainliest what is the surface area of a polyhedron with measurements 4cm x 4cm x 7cm? SOMEONE PLEASE HELP ME WITH THIS !!! YOU ARE HERE, screamed the map in bold red letters. The maze of lines on the map of the Blivet Hotel seemed designed to confuse and disorient the viewer. "We are completely lost," said Penrose with a sigh. "We'll never make it to the conference hall in time for the chess tournament." "You are such a pessimist," Escher chided her brother. "The first match doesn't start for thirty minutes. Surely we'll find the right room by then. The tournament can't go on without you, anywayyou're the main attraction!" "Every floor in this building looks the same," remarked Mobius. "It's like some kind of practical joke by the architect." "Let's try the stairs," Penrose suggested. He led the others to the staircase and began climbing. "Is this the third floor or the fourth floor?" asked Escher, her voice echoing loudly in the stairwell. "This looks like the first floor," Mobius replied with a frown. "How can that be? We've been climbing up for at least two flights." "Someone just sent me a text message," said Penrose. "Maybe it's from one of the tournament organizers." I snuck into the Blivet Hotel and removed all the signs in the building to guarantee that you'll never make it in time, read the message. The sender was his arch-nemesisand his most serious competitorReutersvrd Jones.How would the passage be different if it were told from Reutersvrd Jones' point of view? A. It would make the reader a main character in the story. B. It would let the reader know Penrose's thoughts. C. It would show how Mobius and Escher feel about Reutersvrd. D. It would reveal how Reutersvrd feels about Penrose. Books that contain case decisions from the courts are known as______________. Lena ran in a 340-meter race.About how many feet did she run? At a single-phase, multiple-channel service facility, customers arrive randomly. Statistical analysis of past data shows that the interarrival time has a mean of 20 minutes and a standard deviation of 4 minutes. The service time per customer has a mean of 15 minutes and a standard deviation of 5 minutes. The waiting cost is $200 per customer per hour. The server cost is $25 per server per hour. Assume general probability distribution and no buffer capacity restrictionRequired:a. Find the optimal number of servers to be employed to minimize the total of waiting and server costs.b. Find the average waiting time and the average total time through the system for the optimal case. c. Find the cost per hour, average waiting time, and average flow time for one server if the probability distributions for the interarrival time and service time are assumed to be exponential and the mean values remain the same. . The Gulf of Tonkin Resolution of 1964 provoked Congress to authorize President Johnson's use of military forceagainst the North Vietnamese. What happened in the Gulf of Tonkin to encourage Congress to act? Find the derivative of y=a^x A researcher measured the length of several lizards she found in a field and recorded the data in the box plot shown below. Anthony sold 45 tickets to the school play and Katy sold 40 tickets. What is the ratio of the number of tickets Anthony sold to the number of tickets Katy sold? A 9:8 B 40:45 C 5 to 8 D 8 to 9