# Math Help - Partial derivative problem

1. ## Partial derivative problem

I have repeated this one several times, and keep getting the same answer. But it's marked wrong, can't find my error:

$w = xe^{\frac{y}{z}}$

$x = t^4$
$y = 6 - t$
$z = 1 + 5t$

$\frac{dw}{dt} = e^{\frac{y}{z}}(4t^3) + xe^{\frac{y}{z}}(\frac{1}{z})(-1) + xe^{\frac{y}{z}}(\frac{-y}{z^2})(5)$

$\frac{dw}{dt} = e^{\frac{y}{z}}(4t^3-\frac{x}{z}-\frac{5xy}{z^2})$

If anyone can explain what I have done wrong, I'd be extremely thankful

2. Your answer looks correct. What makes you think it's not? Remember, books contain misprints and professors can be wrong!