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# Divergence of vector r. watch

1. Hi, can someone please explain this to me.
I have the vector field

Taking the divergence using Spherical Polar Coordinates gives me

however, if I convert this to cartesian coordinates I get the divergence to be 3. What is going on here?
2. (Original post by KeyFingot)
Hi, can someone please explain this to me.
I have the vector field

Taking the divergence using Spherical Polar Coordinates gives me

however, if I convert this to cartesian coordinates I get the divergence to be 3. What is going on here?
You need to check your working for the cartesian case - I think you may have made the mistake of thinking that \hat{r}/r = (x,y,z) in cartesian coordinates, which isn't the case (but would give a divergence of 3).
3. (Original post by Mark13)
You need to check your working for the cartesian case - I think you may have made the mistake of thinking that \hat{r}/r = (x,y,z) in cartesian coordinates, which isn't the case (but would give a divergence of 3).
Oh I see now, cheers

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