# Another chain rule: easy one

1. Mar 13, 2008

### physicsed

[SOLVED] another chain rule: easy one

$$y=xe^{-x^2}$$

i have no i dea how to start.
$$f'= x^{x^2} or -2x^blah blah blah$$

just get me started and i'll promise you i will finish it myself

Last edited: Mar 13, 2008
2. Mar 13, 2008

### Feldoh

This is actually an application of the product rule, then the chain rule.

3. Mar 13, 2008

### duke_nemmerle

You will probably want to use the product rule and the rule for finding the derivative of $$e^{g(x)}$$

4. Mar 13, 2008

### rocomath

Product rule!!!

$$f(x)=e^{-x^2}$$

derivative of e is itself, times the derivative of it's exponent.

5. Mar 13, 2008

### rocomath

wow 3 replies all at 22:49 ... you just got the royal treatment :D

6. Mar 13, 2008

### Feldoh

ROFL:rofl:

7. Mar 13, 2008

### Dick

Start with the product rule. When you get to needing to find d/dx(e^(-x^2)) then remember the chain rule says (f(g(x)))'=f'(g(x))*g'(x). f is exp. g(x)=-x^2. So?

8. Mar 13, 2008

### physicsed

Solved it
thanks

9. Mar 13, 2008

### Dick

Geez. I'm really late.

10. Mar 13, 2008

### physicsed

$$Y'= e^{-x2}(1-2x^{2})$$
thanks for the help

11. Mar 13, 2008

### Feldoh

Looks right^^