# Thread: Help with trig substition

1. ## Help with trig substition

How is the following integrated?

$\int \sqrt{1-4x^2} \,dx$

2. try $x = \frac{1}{2}\sin t$

3. I tried that, but I can't find any errors in my work, and I got a different answer than my book did.

4. Show me your workings.

5. I found my error going back over it to type it in. Thanks