# Integrate that by parts for integral

i need help taking this integral

$$\int$$ 9sin$$\sqrt{t+1}$$

help please!!!! i dont even know where to start :[

## Answers and Replies

HallsofIvy
Homework Helper
First write it correctly:
$$\int 9 sin(\sqrt{t+1}) dt$$

Make the obvious substitution $u= \sqrt{t+1}= (t+1)^{1/2}$ so that $du= (1/2)(t+1)^{-1/2}dt$ or 2udu= dt.
(Equivalently, u2= t+ 1.)

That changes your integral to
$$9\int u sin(u)du$$
and you can integrate that by parts.

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