Suppose f:R^n->R is twice differentiable. Prove that f is convex if and only if its Hessian gradiant^2 f(x) is nonnegative.
Not sure how to approach this beside the fact that i'll have to prove in both directions since it's if and only if.
Suppose f:R^n->R is twice differentiable. Prove that f is convex if and only if its Hessian gradiant^2 f(x) is nonnegative.
Not sure how to approach this beside the fact that i'll have to prove in both directions since it's if and only if.