is the first stepc orrect?
yep, everything looks good.
Yes, that's correct.
But (I guess) you've used a trig identity: [itex]z'(t)=2\sin t \cos t=\sin(2t)[/itex] in the last term. This will not make your integral easier. Best leave it as [itex]2\sin t \cos t[/itex].
thank you very much, eok and galileo!
i get 7/6
but when i follow galileo's advice, i get 7/3
please help me verify again. TQ.
The correct answer is 7/3 but it shouldn't matter whether you use that trig identity or not.
tq. i'll try to check back this question later.
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