Prove that the function `f(x)=cos^2x` is strictly decreasing in `(0,pi/2)`

Prove that the function f(x)=cos x is strictly decreasing in (0,pi)

Prove that the function f(x)=cosx is strictly decreasing in (0,\ pi)

f(x) = cos x is strictly decreasing in (0, pi)

Prove that the function f(x)=cos x is strictly increasing in (pi,2 pi)

Prove that the function f(x)=cosx is strictly increasing in (pi,\ 2pi)

Prove that the function f(x)=logsinx is strictly increasing in (0,pi/2) and strictly decreasing in (pi/2,pi)

Show that the function f(x) = cos^(2) x is strictly decreasing on (0, (pi)/(2)) .

Prove that the function f(x)=[x]-x is strictly decreasing on [0,1).

Prove that the function f(X) = cosx is strictly decreasing (0,pi) and strictly increasing on (pi,2pi)