Normalization of time independent wave function

[Skullmonkee]

Homework Statement

normalize the wave function $$\Psi(x)= Acos(\Pi*x/a)$$ to show that A=$$\sqrt{2/a}$$

The Attempt at a Solution

i don't know how to get that answer as all i can tell, normalizing gives:
$$-A^{2}pi^{2}2x/a^{2} * sin (pix/a)$$

However this does not give the right answer for A
Any help pointing out what I've missed would be great.

 

[xepma]

Hi Skullmonkee,

Let me ask you a question first:

What expression "defines" the normalization of a wavefunction?

 

[Skullmonkee]

Do you mean this?

$$\int\Psi^{*}\Psi dx=1$$

$$\int Acos(\pi x/a)*Acos(\pi x/a)dx$$

= $$\int A^{2}cos^{2}(\pi x/a)$$

But I am not sure where to go from here?

 

[Redbelly98]

What are the limits of integration? I.e., over what range of x is the wavefunction defined?

 

[Matterwave]

You need to plug in the limits of integration. You can't normalize a wave function using indefinite integration.