# Thread: Integral help

1. ## Integral help

Integral of sin(3x) / cos^3(3x) dx

2. Originally Posted by element
Integral of sin(3x) / cos^3(3x) dx
$\frac{\sin{3x}}{\cos^3{3x}} = \tan{(3x)}\sec^2{(3x)}$

Can you do it now?

3. Originally Posted by Chop Suey
$\frac{\sin{3x}}{\cos^3{3x}} = \tan{(3x)}\sec^2{(3x)}$

Can you do it now?
Thanks, I can't believe I didn't see that. I tend to think too hard in my DE class.