# Partial Derivative question

1. May 8, 2004

### Spectre32

We went over this breifly in class and i'm confused on it. Were doing first order only and this is the problem: z = 3x^2*y^3*e^(5x-3y) + ln(2x^2 + 3y^3) I know your susposed to Fx(x,y) and treat X or Y as a constant, depending, upon how you want to start, but i'm still unclear as to how to solve this.

Thanks for the help.

2. May 8, 2004

### fourier jr

Well you know how to find an ordinary derivative, so if you need to get Fx, replace y by something else, like a or 17 or pi or whatever, then find the x derivative.

3. May 8, 2004

### Spectre32

So you just single each variable out and thats it?

4. May 8, 2004

You treat the variable you are not differentiating with respect to as any other constant, and then you differentiate normally.

Setting the variable equal to 17 or pi or something would probably confuse lots of people, though...

5. May 8, 2004

### Spectre32

yeah i was confused by that.

6. May 8, 2004

### fourier jr

yeah that's it. Fix one (pretend it's constant), differentiate with respect to the other.