Find the interval for which `f(x)=x-sinx` is increasing or decreasing.

Find the intervals in which the function is (a) increasing, (b) decreasing: f(x) = (x + 1)^(3) (x - 3)^(3) .

Find the interval in which f(x)=2x^(3)+3x^(2)-12x+1 is increasing.

The interval in which y = x^(2) e^(–x) is increasing in

Find the interval in which f(x)=x^(3)-3x^(2)-9x+20 is strictly increasing or strictly decreasing.

Find the intervals in which the functions are strictly increasing or decreasing: -2x^(3)-9x^(2) -12x+1

Find the intervals in which the functions are strictly increasing or decreasing: 6-9x-x^(2)