1. ## integral question

Hello. I have difficulty solving the question int (sqrt(1-x^2)) dx using u=arcsinx. Any ideas would be greatly appreciated. all i was able to do is rewrite it as int (1-x^2)/(sqrt(1-x^2)) dx but im not too sure what to do after this.

2. $\displaystyle u=arcsinx$
$\displaystyle sinu=x$
$\displaystyle dx=cosu \: du$
$\displaystyle \int \sqrt{1-x^2} \: dx= \int \sqrt{1-sin^2 u} \: cos u du=\int cos^2 u \: du$