7. Least squares approximation of functions Let f(x) be a function defined on the interval [-1, 1], as f(x) = {}; -1, 1, -1 x < 0, 0≤ x ≤1. We want to approximate f(x) by a function of the form g(x) = a cos(x)+bsin(x). Find the best possible constants a and b, by the method of least squares.