1. The problem statement, all variables and given/known data z = f (x^2 + y^2) prove using multi var chain rule that y * dz/dx - x * dz/dy = 0 2. Relevant equations 3. The attempt at a solution honestly i just need to no how to start it then im sure i could figure the rest out so i would find dz/dx and dz/dy then what would x and y be? and do i substiude any values of x and y to prove it works?