E9.1 Often we are given certain graphical information about a function instead of a rule. We can use this information to approximate partial derivatives. For example, suppose that we are given a contour plot of the function (instead of a formula) that describe the temperature distribution on a plane region (f(a:,y) is in Fahrenheit, and x, y are measured in miles) Use this contour plot to approximate f2 (4,5) and fy (4,5) as best you can