# Math Help - Integral of sqr(1-x^2)

1. ## Integral of sqr(1-x^2)

Using trig. substitution I get the following:
-theta/2 + sin 2theta + C.

When I write this in terms of x I get -(arccos x)/2 in place of -theta/2 however I am not sure how to convert sin 2theta. If it was just sine theta I wouldn't have a problem.

2. $sin(2 \theta) = 2 sin( \theta) cos( \theta)$

3. So it does. Thanks for that.