Solve Stoke's Theorem with Contour C and Vector Field F for Calculus Homework

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SUMMARY

The forum discussion focuses on solving Stoke's Theorem for a specific contour C and vector field F in a calculus homework problem. The vector field is defined as F = . The initial calculation of the line integral resulted in 27.0833, which was incorrect; the correct answer is 20/3 after adjusting the limits of integration for x from 0 to 2. Additionally, clarity in notation regarding sin(x^2) was emphasized to avoid confusion.

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Homework Statement



\oint_C{(x^2 + 2y + sin x^2)dx + (x + y + cos y^2)dy}

the contour C formed by 3 curves:
C(x,y) = \begin{cases}x=0, \quad from (0,0) to (0,5)\\y = 5 - x^2,\quad from(0,5) to (2,1) \\ 4y = x^2, \quad from(2,1) to (0,0)\end{cases}

and the Stoke Theorem:
\oint_C \vec F \, d\vec r = \iint_S \, curl \, \vec F \, d\vec S \\= \iint_S \, curl \, \vec F \cdot \vec n \, dS

The Attempt at a Solution



So in this problem, can I say the vector field, F as follow?
\vec F = <x^2 + 2y + sin x^2 ,\,\, x + y + cos y^2, \,\, 0>
then
\oint_C \vec F \, d\vec r = \iint_S \, curl \, \vec F \, d\vec S \\ = \int_0^5 \int_\frac{x^2}{4}^{5-x^2} -1\, dy\, dx \\ = 27.0833

but probably there is something wrong in there, because the answer is 20/3
 
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Your x only ranges from 0 to 2, not 0 to 5.
 
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Oh yeah, what a silly mistake, thanks.
 
null void said:

Homework Statement



\oint_C{(x^2 + 2y + sin x^2)dx + (x + y + cos y^2)dy}

the contour C formed by 3 curves:
C(x,y) = \begin{cases}x=0, \quad from (0,0) to (0,5)\\y = 5 - x^2,\quad from(0,5) to (2,1) \\ 4y = x^2, \quad from(2,1) to (0,0)\end{cases}

and the Stoke Theorem:
\oint_C \vec F \, d\vec r = \iint_S \, curl \, \vec F \, d\vec S \\= \iint_S \, curl \, \vec F \cdot \vec n \, dS

The Attempt at a Solution



So in this problem, can I say the vector field, F as follow?
\vec F = <x^2 + 2y + sin x^2 ,\,\, x + y + cos y^2, \,\, 0>
then
\oint_C \vec F \, d\vec r = \iint_S \, curl \, \vec F \, d\vec S \\ = \int_0^5 \int_\frac{x^2}{4}^{5-x^2} -1\, dy\, dx \\ = 27.0833

but probably there is something wrong in there, because the answer is 20/3

Your notation is ambiguous and confusing: does ##sin x^2## mean ##\sin(x^2)## or ##\sin^2 x = (\sin x)^2##?
 
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Ray Vickson said:
Your notation is ambiguous and confusing: does ##sin x^2## mean ##\sin(x^2)## or ##\sin^2 x = (\sin x)^2##?
it is sin(x^2), i will make it clear next time
 

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