1. Find the local maximum and minimum values and saddle point(s) of the function. If you have three-dimensional graphing software, graph the function with a domain and viewpoint that reveal all the important aspects of the function. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.) f (x, y) = x² + xy + y² + 5y

The graph of fx=1/x is a .

A company that makes and sells baseball caps has found that the total monthly cost C in dollars of producing x caps is given by the function C(x)=0.2x280x+9000. Find the production level that will minimize the monthly cost and find the minimum cost.

A company determines that its weekly profit from manufacturing and selling x units of a certain item is given by Px=-x3+3x2+2880x-500. Use a graphing utility to find the weekly production rate that will maximize the profit.