Question

\[Evaluate \int\limits x ^{3}\cos ^{5}x ^{4}sinx ^{4}dx\]

Answer 1

try starting with

let u = x^4
du = 4x^3

so the integral becomes
\[\frac 14 \int \cos^5 (u) \sin (u )du\]
does that help?

Answer 2

yes. thanks. :)