## anonymous 5 years ago please integrate sine^3x ???

$\int\limits_{}^{}\sin (3x) \ dx$ Perform a substitution, where $u = 3x \ \ du = 3 \ dx \ \ \frac{1}{3}du = 1 \ dx$ Then you have an integral $\frac{1}{3} \int\limits\limits_{}^{}\sin (u) \ du = -\frac{1}{3}\cos(u) + c$ Substitute u = 3x back in and you'll have your answer $-\frac{1}{3}\cos(3x) + c$