Question

find the indefinite integral :
integral(sin(4x)^3 cos(4x)^4)dx

Answer 1

Start with u = 4x and du = 4x dx

Answer 2

Now apply the reduction formula.

Answer 3

Did you get it?

Answer 4

wouldn't you want to make the substitution:
\[\sin^{3}(4x) = \sin(4x)(1-\cos^{2} (4x))\]
\[u = \cos(4x)\]
\[du = -4\sin (4x) dx\]
\[\rightarrow -\frac{1}{4}\int\limits_{}^{}(1-u^{2})u^{4} du\]

Answer 5

@dumbcow nice one! Its a lot less messier!

Answer 6

thanks
sgamam, can you finish from there

Answer 7

yeah I just finished it thank you both so much for the help!