# Math Help - why these expression are the same..

1. ## why these expression are the same..

on the bottom of this page we have an expression which represents all solutions
http://i45.tinypic.com/140hqtx.jpg

but
later
in here
http://i45.tinypic.com/2nrfswm.jpg

they present another expression and say that its the same as the integral before(all the solutions)

why they are the same??

2. Originally Posted by transgalactic
on the bottom of this page we have an expression which represents all solutions
http://i45.tinypic.com/140hqtx.jpg

but
later
in here
http://i45.tinypic.com/2nrfswm.jpg

they present another expression and say that its the same as the integral before(all the solutions)

why they are the same??

He's just putting $\psi(x)=\int\limits_{-\infty}^\infty A(k)e^{ikx}dk$ in the second expression, that's all.

Tonio

3. ahh thanks