1. The problem statement, all variables and given/known data Find the equilibrium points for the following equation. Determine if the equilibrium points are stable and if stable,approximate the angular frequency. (i) d2y/dx2 = cosh(x). 2. Relevant equations 3. The attempt at a solution For equilibrium points, do we need to find dy/dx = 0 or d2y/dx2 = 0 or both? Thank you.