Partial Derivatives

Question

Let a and b be positive constants. Let R(x,y) = bx^(a)y^(b)

1. Calculate x(∂R/∂x) + y(∂R/∂y).

2. Calculate (a + b)R(x,y).

3. How are the two expressions above related?


I know how to find partial derivatives in general, but I am still at a lost as to how to solve this problem. 

Answer 1

I can get you started with the partial derivative ∂R/∂x = abx^(a-1)y^b.  Have you gotten that far?