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mlainz
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Gradient, divergence and curl with covariant derivatives

I am trying to do exercise 3.2 of Carol Sean's Spacetime and geometry. I have to calculate the formulas for the gradient, the divergence and the curl of a vector field using covariant derivatives.

The covariant derivative is the ordinary derivative for a scalar,so

$$D_\mu f = \partial_\mu f$$

Which is different from

$${\partial f \over \partial r}\hat{\mathbf r} + {1 \over r}{\partial f \over \partial \theta}\hat{\boldsymbol \theta} + {1 \over r\sin\theta}{\partial f \over \partial \varphi}\hat{\boldsymbol \varphi}$$

Also, for the divergence, I used

$$\nabla_\mu V^\mu=\partial_\mu V^\nu + \Gamma^{\mu}_{\mu \lambda}V^\lambda = \partial_r V^r +\partial_\theta V^\theta+ \partial_\phi V^\phi + \frac2r v^r+ \frac{V^\theta}{\tan(\theta)} $$

Which didn't work either.

I was going to try

$$(\nabla \times \vec{V})^\mu= \varepsilon^{\mu \nu \lambda}\nabla_\nu V_\lambda$$

But I think that that will not work. What am I missing?

mlainz
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