The function which is neither decreasing nor increasing in `(pi/2,(3pi)/2)`is

Which one of the following is true? For the function f(x)= cos x f is neither increasing nor decreasing in (pi, 2pi)

Prove that the function f(x)=cos x is neither increasing nor decreasing in (0,2 pi)

Prove that the function f(x)=cosx is neither increasing nor decreasing in (0,\ 2pi)

f(x) = cos x is neither increasing nor decreasing in (0,2pi)

Show that the function given by f(x)=sinx is neither increasing nor decreasing in (0,pi)

Prove that the function x^2 + x+1 is neither increasing nor decreasing on (-1,0)

Show that the function x^2 - x+1 is neither increasing nor decreasing on (0,1).

Show that the function x^2-x+1 is neither increasing nor decreasing on (0,\ 1) .

Show that the function x^(2)-x+1 is neither increasing nor decreasing on (0,1).

Show that the function given by f(x) = sinx is neither increasing nor decreasing in (0, pi) .