Section 14.7: Max Min Problems

Use a graph or level curves or both to estimate the local maximum and minimum values and saddle point(s) of the function \(f(x, y) = \sin x + \sin y + \sin(x + y)\), \(0 \le x \le 2\pi\), \(0 \le y \le 2\pi\). Then use calculus to find these values precisely.