Question

find the total differential of the function.
f(x,y) = 5y/x-y

Answer 1

df = ∂f/∂x dx + ∂f/∂y dy

f = 5y/(x-y)
df = -5y/(x-y)^2 dx + 5x/(x-y)^2 dy
= 5/(x-y)^2 (x dy - y dx)