Question

On which interval(s) is
f(x)=x^4−2x^2−7 decreasing?

Answer 1

I know the critical points are -1, 0. 1. I don't know what to do from there.

Answer 2

the answer is (-INF, -1), (0, 1) but I don't know how to get it :/

Answer 3

just find the derivative
and that derivative should be negative that is less than zero
solve the inequality

Answer 4

@RED123url how do i do that?