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2 years ago

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Mathematics

1 answer:

amid [387]2 years ago

7 0

Answer:

21.56

Step-by-step explanation:

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Consider the line integral Z C (sin x dx + cos y dy), where C consists of the top part of the circle x 2 + y 2 = 1 from (1, 0) t

pashok25 [27]

Direct computation:

Parameterize the top part of the circle $x^2+y^2=1$ by

$\vec r(t)=(x(t),y(t))=(\cos t,\sin t)$

with $0\le t\le\pi$ , and the line segment by

$\vec s(t)=(1-t)(-1,0)+t(2,-\pi)=(3t-1,-\pi t)$

with $0\le t\le1$ . Then

$\displaystyle\int_C(\sin x\,\mathrm dx+\cos y\,\mathrm dy)$

$=\displaystyle\int_0^\pi(-\sin t\sin(\cos t)+\cos t\cos(\sin t)\,\mathrm dt+\int_0^1(3\sin(3t-1)-\pi\cos(-\pi t))\,\mathrm dt$

$=0+(\cos1-\cos2)=\boxed{\cos1-\cos2}$

Using the fundamental theorem of calculus:

The integral can be written as

$\displaystyle\int_C(\sin x\,\mathrm dx+\cos y\,\mathrm dy)=\int_C\underbrace{(\sin x,\cos y)}_{\vec F}\cdot\underbrace{(\mathrm dx,\mathrm dy)}_{\vec r}$

If there happens to be a scalar function $f$ such that $\vec F=\nabla f$ , then $\vec F$ is conservative and the integral is path-independent, so we only need to worry about the value of $f$ at the path's endpoints.

This requires

$\dfrac{\partial f}{\partial x}=\sin x\implies f(x,y)=-\cos x+g(y)$

$\dfrac{\partial f}{\partial y}=\cos y=\dfrac{\mathrm dg}{\mathrm dy}\implies g(y)=\sin y+C$

So we have

$f(x,y)=-\cos x+\sin y+C$

which means $\vec F$ is indeed conservative. By the fundamental theorem, we have

$\displaystyle\int_C(\sin x\,\mathrm dx+\cos y\,\mathrm dy)=f(2,-\pi)-f(1,0)=-\cos2-(-\cos1)=\boxed{\cos1-\cos2}$

3 0

3 years ago

A shoe box in the shape of a right rectangular prism has a base that measures 7 inches by 12 inches and is 5 inches high. What i

AlekseyPX

Answer:

The volume of the shoe box is 420 cubic inch

Step-by-step explanation:

This problem bothers on the mensuration of solid shapes, a righ rectangular prism

Given data

Length of prism l= 12inches

Width of prism w= 7 inches

Height of prism h= 5 inches

We know that the volume of a rectangular prism is expressed as

Volume =l*w*h

Volume = 12*7*5= 420in³

6 0

3 years ago

Read 2 more answers

What is the circumference of a circle with a diameter 9cm

xz_007 [3.2K]

The circumference follows the formula
C= 2 (pi)R
R is the radius which is half the diameter when we put this into the equation we get
C = 2 (pi)(4.5)
C=28.274334

5 0

3 years ago

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Question 4 (1 point)<br> (-7x + 5) - (-82 – 6) =

Keith_Richards [23]

no ye puedo ayudar amigo o amiga

8 0

3 years ago

When Jasper won the jackpot prize of

denpristay [2]

Answer:m

Step-by-step explanation: