1. The problem statement, all variables and given/known data Here is the question with the solution: http://dl.dropbox.com/u/64325990/MATH%20253/midterm%202.PNG [Broken] I don't understand how to do a. How did they know to use x=0 and y=0 for Fx(0,0) and Fy(0,0)? I understand that this is implicit differentiation using Chain Rule where dy/dx = -Fx/Fy But g'(0) only tells us that x=0 but tells us nothing about y. So how would they know to use y=0 as well? Edit: Also does anyone have an idea how to start part b g''(0)?