## AmTran_Bus one year ago d/dx of (x^3+2x)e^x

1. AmTran_Bus

I used the chain rule, but chegg says the product rule. Why? I got e^x(x^3+2x)*3x+2

2. AmTran_Bus

@Zale101

3. zepdrix

product ruleeee :)

4. AmTran_Bus

But why? guess I dont understand the concept.

5. zepdrix

$\Large\rm \frac{d}{dx} (x^3+2x)e^x=\color{orangered}{(x^3+2x)'}e^x+(x^3+2x)\color{orangered}{(e^x)'}$

6. zepdrix

You have two x-thingy's being multiplied together, that's called a product

7. AmTran_Bus

Would I have used the chain rule if the (x^3+2x) had of been squared or cubed?

8. zepdrix

Chain rule is when you have a function inside of a function. Product rule you apply when you have a function next to a function.

9. zepdrix

Yes. Good.

10. AmTran_Bus

Ok. I think I got it now. Thanks.