Are these correct?

[Rsls79]

Any help appreciated. Are these two problems correct?

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[stapel]

Are these two problems correct?

I'm sorry, but I have no idea whether or not whatever you're doing is correct. What are you doing? Are you maybe integrating something? If so, what? If not, what were the original exercises and their instructions?

Thank you.

Eliz.

 

[Rsls79]

the first i'm just to simplify the problem using trig identities like
sin[theta]/cos[theta]=tan[theta] or cos[sqrd theta] + sin[sqrd theta] = 1

the second im to substitue t=5 sin u into t[sqrt]25-t[sqrd] and simplify