f(x) is monotically decreasing

Let f(x) =x^(3) - 6x^2 +9x +18 , then f(x) is strictly decreasing in …………

Let f(x)=x^(3)-6x^(2)+9x+18 , then f(x) is strictly decreasing in :

f(x)=|xlog_(e )x| monotonically decreases in

f(x) = |x log_(e) x| monotonically decreases in

The function f(x) = a^x is strict decreasing on R, If

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

let h(x)=f(x)-[f(x)]^(2)+[f(x)]^(3) for every real number x. Prove that h(x) is increasing or decreasing according as f(x) is increasing or decreasing.

If g(x) is a decreasing function on R and f(x)=tan^(-1){g(x)}. State whether f(x) is increasing or decreasing on R.