How do you evaluate the definite integral #int 2(pi)x(cos^(-1)(x))dx# from 0 to 1?
1 Answer
Explanation:
Before beginning, we should know or determine that
Working first with the unbounded integral, we should apply integration by parts. Let:
#{(u=cos^-1x,=>,du=(-1)/sqrt(1-x^2)dx),(dv=xdx,=>,v=x^2/2):}#
Then:
On the remaining integral, let
Simplifying:
#=1/2theta-1/2sinthetacostheta=1/2sin^-1x-1/2xsqrt(1-x^2)#
Plugging this into our previous expression:
Now applying the bounds, the original integral equals:
#=picos^-1(1)+pi/2sin^-1(1)-(pi/2sin^-1(0))#
#=pi/2(pi/2)=pi^2/4#