a.
\(\int2\left(2sinx+1\right)^3cosxdx\)
Đặt \(2sinx+1=u\Rightarrow2cosxdx=du\Rightarrow2cosxdx=du\)
\(\Rightarrow I=\int u^3du=\dfrac{1}{4}u^4+C=\dfrac{1}{4}\left(2sinx+1\right)^4+C\)
b.
Đặt \(1-cosx=u\Rightarrow sinxdx=du\)
\(\Rightarrow I=\int u^4du=\dfrac{1}{5}u^5+C=\dfrac{1}{5}\left(1-cosx\right)^5+C\)