Derivative of Lx^2+Ly^2+Lz^2 =?

[rasi]

Thanks for your helpings...

 

[DrClaude]

In $L_x$, it should be $\cos \phi$, not $\cot \phi$. $L_z$ has the wrong sign.

 

[rasi]

In $L_x$, it should be $\cos \phi$, not $\cot \phi$. $L_z$ has the wrong sign.

So how can i go on. In no way i coulnd't tackled it. Thanks for your help...

 

[DrClaude]

So how can i go on. In no way i coulnd't tackled it. Thanks for your help...

Not sure what you mean here.

Can you describe the problem you want to solve? The title of the thread is not very clear, do you mean you need to write $L_x^2 + L_y^2 + L_z^2$ in spherical coordinates $(\theta, \phi)$?

 

[rasi]

Not sure what you mean here.

Can you describe the problem you want to solve? The title of the thread is not very clear, do you mean you need to write $L_x^2 + L_y^2 + L_z^2$ in spherical coordinates $(\theta, \phi)$?

yes. just as you said.

 

[DrClaude]

Then you need to calculate each term by applying it to itself, e.g.,
$$
L_z^2 = L_z L_z = -i \hbar \frac{\partial}{\partial \phi} \left( -i \hbar \frac{\partial}{\partial \phi} \right)
$$