## difficult integration

integrate sin^4(2x) without using the reduction formula.im stuck.
im pretty sure you have to use integration by parts.

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 Try using double-angle formulae a couple of times.
 Recognitions: Homework Help The double angle formula for cos will help I believe.

## difficult integration

don't know what the reduction formula is, maybe it is the trick i'm about to give you

$$\int sin(2x)^4 dx = \frac{1}{2} \int sin(u)^4 du = \frac{1}{2} \int (sin(u)^2)^{3/2} sin(u) du = \frac{1}{2} \int (1-cos(u)^2)^{3/2} sin(u)du = \frac{1}{2} \int (1-t^2)^{3/2} dt = \int sqrt((1-t^2)^3)$$

maybe you can do this???, of cause you have to keep track of all the substitutions to get how sin and y are related but that should be possible.

 This thread is already somewhere else. I mean the exact same question. http://www.physicsforums.com/showthread.php?t=213617