Question

Session 69 Problem

Answer 1

I believe the answer to session 69's problem might be wrong.
Compute: \[\int\limits_.\sin4(x) \cos2(x) dx.\]sin4(x) cos2(x) dx.

The answer goes onto say that \[\int\limits_.\cos ^{2}(2x) = x/2 +\sin(2x)/4 + c\]
... but shouldn't this be ...
\[\int\limits_.\cos ^{2}(2x)= x/2 + \sin(4x)/8\]

Resulting in the final answer ...
=> x/16 - sin(4x)/64 - sin^{3}(2x)/48 + c
???

Thanks!

Answer 2

Yes, I agree with your result. Every now and then I have come across mistakes in the write-up. This appears yet another.