How do you simplify sin(cos^-1x)sin(cos1x)?

1 Answer
Sep 25, 2016

:. sin(cos^-1x)=sqrt(1-x^2).

Explanation:

Let cos^-1x=theta, |x|le1," so that, "sin(cos^-1x)=sintheta.

"By the Defn. of "cos^-1" fun.," cos^-1x=thetarArrcostheta=x,

where, theta in [0,pi].

" Reqd. Value="sintheta=+-sqrt(1-cos^2theta)=+-sqrt(1-x^2).

But, theta in [0,pi] rArr sinthetage0

:." Reqd. Value="+sqrt(1-x^2).

:. sin(cos^-1x)=sqrt(1-x^2).