I need to determine the interval on whhich f(x) = x - x^(-2) is increasing. I think I should first get the derivative: F' = 1 - (-2x^-3)

= 1 + 2x^-3

= 1 + 2/x^3

I hope I wrote the function = x minus x to the minus 2. I derived 1 + 2 divided by x cubed. Even if I got the derivative right, I do not know how to use this derivative to determine when the function is increasing. Do I make the derivative greater than zero? Please help.