# Math Help - I get a similar answer for this integral

1. ## I get a similar answer for this integral

I am trying to solve this integral:
http://www.wolframalpha.com/input/?i=integral+(sin(4x))^2+*+(cos(4x))^2

and I was just wondering what I am doing wrong (my work is attached).

Any input would be greatly appreciated!
Thanks in advance!

2. Originally Posted by s3a
I am trying to solve this integral:
http://www.wolframalpha.com/input/?i=integral+(sin(4x))^2+*+(cos(4x))^2

and I was just wondering what I am doing wrong (my work is attached).

Any input would be greatly appreciated!
Thanks in advance!
Hello,
You did a substitution then you ignore it.
you have mistake in the third line. The denominator should be 4 not 2.
And you forgot the $dx$ twice.
Its better to evaluate by the substitution $w=4x$, which will make it:
$\int_0^{32} sin^2(w) cos^2(w) = ...$
Try it again.