I have a question that I would just like a little bit of clarification about.
Find a and b, 0 < a 1, 0 < b 1 such that max x is element of [−1,1] |(x + b)(x + a)(x − a)(x − b)| = max x is element of [−1,1] |(x2 − a2)(x2 − b2)| be as small as possible.
In class my teacher said that Si(x) = 2x(x^2-a^2) + 2x(x^2-b^2) = 0.
I know why we set it equal to zero but where does the left side of the equation come from? I cannot figure this out and would appreciate any help!