What is the partial derivative?

Question

for x=5Q/(3+Z)

Show that cross partial derivatives are equall

Answer 1

∂x / ∂Q = 5 / (3 + Z)
So ∂(∂x / ∂Q) / ∂Z= -5 / (3 + Z)²

and
∂x / ∂Z = - 5Q / (3 + Z)²
so ∂(∂x / ∂Z) / ∂Q = -5 / (3 + Z)²

∂²x / ∂Z∂Q - ∂²x / ∂Q∂Z= - 5 / (3 + Z)²+5 / (3 + Z)²=0

Answer 2

∂x / ∂Q = 5 / (3 + Z)
∂x / ∂Z = - 5Q / (3 + Z)²
Not sure what you mean by CROSS partial derivative.

Answer 3

trying to get others to do your homework is just shameful. SHAMEFUL!!