Directional Derivatives & Gradient / Optimization / Constrained Optimization: Lagrange Multipliers / Multiple Integrals / Double Riemann Sums & Double Integrals over Rectangles / Iterated Integrals / Double Integrals over General Regions / Applications of Double Integrals / Double Integrals in Polar Coordinates / Surfaces Defined Parametrically & Surface Area / Triple Integrals / Triple Integrals in Cylindrical & Spherical Coordinates / Change of Variables