How do you integrate sin2(x)dx using integration by parts?

1 Answer
Nov 3, 2015

sin2(x)dx=x2sin(2x)4+c,
where c is the constant of integration.

Explanation:

sin2(x)dx=ddx(x)sin2(x)dx

=xsin2(x)xddx(sin2(x))dx

=xsin2(x)x(2sin(x)cos(x))dx

=xsin2(x)xsin(2x)dx

=xsin2(x)+12xddx(cos(2x))dx

=xsin2(x)+12[xcos(2x)ddx(x)cos(2x)dx]

=xsin2(x)+12xcos(2x)12cos(2x)dx

=xsin2(x)+12xcos(2x)sin(2x)4+c,
where c is the constant of integration.

=x2(cos(2x)+2sin2(x))sin(2x)4+c

=x2sin(2x)4+c