Suppose U(x,y)=4x²+3y²

1. calculate daba U over daba x, daba U over daba y
2. evaluvate these partial derivatives at x=1, y=2
3. write the total differential for U
4. calculate dy/dx for dU=0-that is, what is implied trade-off between x and y holding U constant?
5. show u=16 when x=1, y=2