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

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

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

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

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

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

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

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

Is the function f(x) = cos x strictly increasing in (0, pi) ?