# Angular Momentum operators

1. May 25, 2010

### hhhmortal

1. The problem statement, all variables and given/known data

Hi, my problem is with part two of the question I've attached. I'm not exactly sure what they are expecting me to do, is it simply calculating the expectation value of L_z , from the wavefunction given (i.e. cos(φ))

Thanks.

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2. May 25, 2010

### nickjer

Not sure what part you have a problem with. I am assuming the 2nd paragraph. They basically want you to decompose the cosine into a superposition of eigenfunctions. The magnitude squared of the coefficients for each eigenfunction will give you the probability of that state.

3. May 26, 2010

### hhhmortal

Oh yes, forgot about decomposing cosine and sine.

I got another question, which is, if given a wave function like

u = Acosine(Pi/2a) + B sin(Pix/a)

How would I sketch the form of this squared (i.e. the probability distribution)?

4. May 26, 2010

### nickjer

The first term looks like a constant, so you would just sketch the 2nd term and have it raised or lowered vertically by a constant. Unless you mistyped the first term.