[Johnny010]

Hey there. Here is a question from a 2nd year paper on Physical Chemsitry.

The complex wavefunction f(x) = 1/2 [cos(3x/L) + i(sin (3x/L))]  is an eigenfunction of
the momentum operator. What is the eigenvalue?
Hint: rewrite the function in polar form and then use d/dx(ae_bx=abe^ax

I know a polar representation of say z = x + iy would be z=(modulus of z) e^i*arg(z)

So would the first part be:

f(x)=1/2(cos (3x/L))e^{i(sin (3x/L))}

?