i have this

i set

differentiating z w.r.t , i have

substituting

i recall that

i tend to be confuse from here onward, pls help!

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- March 26th 2013, 04:34 AMlawochekeltrig-substitution!
i have this

i set

differentiating z w.r.t , i have

substituting

i recall that

i tend to be confuse from here onward, pls help! - March 26th 2013, 05:09 AMsmatikRe: trig-substitution!
you'll get cos^2thetha when you'll put 1-sin^2theta=cos^2theta. then you can expand cos^2theta as (cos2theta+1)/2...then integrate cos2theta/2 and 1/2 separately...

- March 29th 2013, 05:01 PMx3bnmRe: trig-substitution!

Now:

By plugging into , and we get:

And that's it. That's the answer. If you differentiate the new found answer with CAS(like maple) you'll get what you started with which is the given integral in the question. Hope this helps.