How do I find the integral intsin^-1(x)dx ?

1 Answer
Sep 10, 2014

By integration by parts,
int sin^{-1}xdx=xsin^{-1}x+sqrt{1-x^2}+C

Let us look at some details.
Let u=sin^{-1}x and dv=dx.
Rightarrow du={dx}/sqrt{1-x^2} and v=x

By integration by parts,
int sin^{-1}xdx=xsin^{-1}x-intx/sqrt{1-x^2}dx

Let u=1-x^2. Rightarrow {du}/{dx}=-2x Rightarrow dx={du}/{-2x}

intx/sqrt{1-x^2}dx=int x/sqrt{u}{du}/{-2x}=-1/2intu^{-1/2}du
=-u^{1/2}+C=-sqrt{1-x^2}+C

Hence,
int sin^{-1}xdx=xsin^{-1}x+sqrt{1-x^2}+C