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# Integrate watch

1. Integrate

1) 9t sint dt

which I think is -9t cost + 9 sint + c

2) 12 sin^2t cost dt

which I think is -6 cos^2t + c

2. Agree with the first one.

For the second, the best thing to try is the substitution u=sint, from which the solution flows quite nicely.
3. How do you sub in u for sin2t?
4. How do you sub in u=sint for sin2t?
How do you sub in u=sint for sin2t?
You would probably have to change the sin2t to 2sintcost.

There's no direct way of subbing it in.

Got a question in mind?

EDIT: Or do you mean sin^2t? Which is what your question 2 says atm. In which case its just u^2.
6. if it is power two, then let sub u=cosx so that makes
integrate 12 (sin t)^2 d(sint)

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Updated: April 3, 2011
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