Đặt \(\left\{{}\begin{matrix}u=x^3\\dv=sinxdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=3x^2dx\\v=-cosx\end{matrix}\right.\)
\(\Rightarrow I=-x^3.cosx|^1_0+3\int\limits^1_0x^2cosxdx=-cos1+3\int\limits^1_0x^2cosxdx\)
Đặt \(\left\{{}\begin{matrix}u=x^2\\dv=cosxdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=2xdx\\v=sinx\end{matrix}\right.\)
\(\Rightarrow I=-cos1+3\left(x^2sinx|^1_0-2\int\limits^1_0x.sinxdx\right)=-cos1+3sin1-6\int\limits^1_0x.sinx.dx\)
Đặt \(\left\{{}\begin{matrix}u=x\\dv=sinxdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=dx\\v=-cosx\end{matrix}\right.\)
\(\Rightarrow I=-cos1+3sinx-6\left(-x.cosx|^1_0+\int\limits^1_0cosxdx\right)\)
\(=-cos1+3sin1+6cos1-6.sinx|^1_0=5cos1-3sin1\)
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