# Differentiating with respect to

1. Jan 12, 2007

### cabellos

differentiating with respect to....

I have a question on differentiating the function z/(2x + y) with respect to x.

Is the answer -2z/(2x + y)^2 ?

Thanks

2. Jan 12, 2007

### moe_3_moe

yes absolutely right... z and y are constant with respect to x

3. Jan 12, 2007

### TD

The other way arround actually, if z and y are constant wrt x, then your answer (the partial derivative of the function wrt x) is right

4. Jan 12, 2007

### HallsofIvy

If z and y are NOT "constant with respect to x", but are functions of x, then you would use the chain rule.