Solve the integral of x²cosxdx, using integration by parts.
"\\int x^2cos(x)dx=x^2sin(x)- \\int sin(x).2xdx=x^2.sin(x)-2\\int x.sin(x)dx"
"u=x^2 \\space \\space \\space du=2x \\space dx"
"dv=cos(x)dx \\space \\space \\space v=sin(x)"
"x^2sin(x)-2(x.(-cos(x)- \\int-cos(x)dx)=x^2sin(x)-2(-xcos(x)+ \\int cos(x)dx"
"u=x \\space \\space \\space \\space du=dx"
"dv=sin(x)dx \\space \\space \\space \\space \\space v=-cos(x)"
"=x^2.sin(x)+2xcos(x)-2sin(x)+C"
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