- #1
hover
- 343
- 0
Homework Statement
Consider the scalar field
[tex] V = r^n , n ≠ 0[/tex]
expressed in spherical coordinates. Find it's gradient [itex]\nabla V[/itex] in
a.) cartesian coordinates
b.) spherical coordinates
Homework Equations
cartesian version:
[tex]\nabla V = \frac{\partial V}{\partial x}\hat{x} + \frac{\partial V}{\partial y}\hat{y} + \frac{\partial V}{\partial z}\hat{z} [/tex]
spherical version:
[tex] \nabla V = \frac{\partial V}{\partial r}\hat{r} + \frac{1}{r}*\frac{\partial V}{\partial \phi}\hat{\phi} + \frac{1}{r*sin(\phi)}*\frac{\partial V}{\partial \theta}\hat{\theta} [/tex]
conversion:
[tex] r = (x^2+y^2+z^2)^\frac{1}{2} [/tex]
The Attempt at a Solution
a.) using the third equation...
[tex] V = r^n = (x^2+y^2+z^2)^\frac{n}{2} [/tex]
using the first equation and skipping some steps involving the chain rule...
[tex] \nabla V = \frac{n(x\hat{x}+y\hat{y}+z\hat{z})}{(x^2+y^2+z^2)^\frac{n}{2}} [/tex]
b.)Using the second equation
[tex] \nabla V = nr^m \hat{r} [/tex]
[tex]m = n-1[/tex]
Those are my two solutions to this problem. Are these right? Are they wrong? If so where did I go wrong?
Thanks!
hover