How Do You Solve the Second Derivative of a Potential Function in Physics?

[cpamieta]

Homework Statement

Well this is a physics problem, need find the potential function

Homework Equations

$\Psi$ =Axe^-kx A and k are constants
I need to find d² $\Psi$/dx²

The Attempt at a Solution

I thought u would just take the derivative two times
but just d$\Psi$/dx = Ae^-kx-kAxe^-kx
Would i do something like this?
http://tutorial.math.lamar.edu/Classes/DE/Linear.aspx
thanks

 

[vela]

What's the problem with just differentiating it again?

 

[cpamieta]

i forgot how you do a differential equation, i have the solutions. I want to know how you do the dΨ/dx
i thought it would just be dΨ/dx= -A/ke^-kx Its been a long summer lol

 

[vela]

You don't have a differential equation. You're simply differentiating a function twice.

For this particular function, you need to use the product rule and chain rule, and you need to know how to differentiate a polynomial and an exponential.

 

[cpamieta]

o ok thxs the wolfan alpha thing said it was when i typed it in. It also gave somthing different