In Exercises 2130, perform the addition or subtraction and write the result in standard form.

Calc III Lec Day _ 10/_/16 Ch. 13.5 Directional Derivatives 1. The derivative of a function, f(x,y), in the direction of unit vector u =(a1,a2) is equal to the product of the partial derivatives of f with the components of u a. 2. This can be extended to functions of more variables by the addition of the products of the additional partial derivatives...