# Eigen Function, Help me

1. Nov 17, 2014

### Alekside

Hello
today i learn about Eigen Function, I have many problem about Eigen Fuction

I not understand what the Eigen Fuction, Eigen Vector, Eigen Value?

For Example I not Understand this problem,
show the sinh 2x as not a Eigen Function d2/dx2, Although the equation as d2/dx2 sinh2x = 4 sinh 2x

2. Nov 17, 2014

### Staff: Mentor

Its a concept from linear algebra, but via that wondrous subject known as functional analysis :p:p:p:p:p, and that the solutions of differential equations form a vector space, and indeed functions with rather weak crireria such as being square intergrable, also form a vector space, it is carried over to that as well:
http://tutorial.math.lamar.edu/Classes/DE/BVPEvals.aspx

Hopefully the above link will allow you to nut it out.

Its well worth your time as, not just in QM, but in applied math in general, its an EXTREMLY important copncept.

Thanks
Bill

3. Nov 17, 2014

### Alekside

well thanks verry much bill, I will read a minute about QM, so thanks

4. Nov 18, 2014

### Staff: Mentor

No problem.

If you are still having problems do post back - on this or any issue.

It fairly easy to actually do your question, but its a lot better if you nut it out and do it.

Thanks
Bill