# integration helpppppp

• February 26th 2008, 12:46 PM
simsima_1
integration helpppppp
$

\int sin{^2}(x)cos{^4}(x)

$

i did it all the way to

$

\frac {1}{8} \int sin{^2}(2x)+sin{^2}(2x)cos(2x)

$

then i split it up and have no idea what happens next...
• February 26th 2008, 12:49 PM
Jhevon
Quote:

Originally Posted by simsima_1
$

\int sin{^2}(x)cos{^4}(x)

$

i did it all the way to

$

\frac {1}{8} \int sin{^2}(2x)+sin{^2}(2x)cos(2x)

$

then i split it up and have no idea what happens next...

hopefully your last line is right, i didn't check. it looks a little fishy to me.

anyway, note that $\sin^2 2x = \frac {1 - \cos 4x}2$. so you can easily integrate the first part

for the second part, use the substitution $u = \sin 2x$