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- Thread starter jkh4
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JasonRox

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What is the derivative to -cos(xy)?

That should help to where the y is going.

That should help to where the y is going.

- #3

nrqed

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I am assuming that the a and b are the limits of integration.

And I am assuming that y is a constant here (it's independent of x). Then this is the simplest type of substitution: just define a new variable z=xy. What is dx then? You should then integrate easily (watch out about changing the limits of integration though if you leave your answer in terms of z).

- #4

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how do you integrate x(y^2 - x^2)^(1/2)? my TA says the answer is (-1/3)((y^2 - x^2)^(3/2)) but i don't get where is the (-1/3) comes from....

- #5

JasonRox

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how do you integrate x(y^2 - x^2)^(1/2)? my TA says the answer is (-1/3)((y^2 - x^2)^(3/2)) but i don't get where is the (-1/3) comes from....

Did you not do any substitution rules or anything?

Where is the work for this? Follow the work and it should be clear where it came from.

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(x^2/2)((y^2-x^2)^(3/2))/(3/2)(-1/x^2)

but one thing i don't understand, for the (-1/X^2), is this a proper intergral step?

- #7

JasonRox

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(x^2/2)((y^2-x^2)^(3/2))/(3/2)(-1/x^2)

but one thing i don't understand, for the (-1/X^2), is this a proper intergral step?

What?

Where does all this come from?

- #8

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nevermind , i got it

Last edited:

- #9

HallsofIvy

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