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

Find the intervals in which f(x)=-2x^(3)-9x^(2)-12x+1 is increasing or decreasing.

Find the intervals in which f(x)=2x^(3)-9x^(2)+12x-5 is increasing or decreasing.

Find the intervals in which f(x)=2x^(3)-12x^(2)+18x+15 is increasing or decreasing.

Find the intervals in which f(x)=2x^(3)+9x^(2)+12x+20 is increasing or decreasing.

Find the intervals in which f(x) = 2x^(3) - 9x^(2) - 12 x -3 is increasing and the intervals in which f(x) is decreasing.

Find the intervals in which f(x)=2x^(3)-15x^(2)+36x+1 is increasing or decreasing.

Find the intervals in which f(x)=-2x^3-9x^2-12 x+1 is increasing or decreasing.

Find the intervals in which f(x)=x^(3)-12x^(2)+36x+17 is increasing or decreasing.

Find the intervals in which f(x)=3x^(4)-4x^(3)-12x^(2)+5 is increasing or decreasing.