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I am using GRQUICK package for calculation of Ricci tensors. I am using a non diagonal metric with coefficients being functions of two co-ordinates. I want to know if the highlighted expression denotes partial derivates or something entirely different.

Astronomer
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    It represents derivative of v[r,theta] w.r.t theta once. – zhk Feb 22 '17 at 07:14
  • You can caopy and paste and use FullForm to check what is there. – Kuba Feb 22 '17 at 07:19
  • Thanks !! v[r,theta] w.r.t theta once.. Could you tell me the logic to understand that ? r corresponds to 1 while theta corresponds to 2. For example what would you make of v(2,0) term similarly ? – Astronomer Feb 22 '17 at 07:20

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Well, you need to see help on D. 

D[v[r, t], t]  (*it gives partial derivative of v w.r.t t once*)

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Here the superscript (0,1) means that v[r,t] is partially differentiated once w.r.t t thats why you have 1 on right side because in the argument [r, t], t is on the right side.

Now, if you want to differentiate v w.r.t r, then

D[v[r, t], r]  (*it gives partial derivative of v w.r.t r once*)

Blockquote

D[D[v[r, t], r], r]  (*it gives partial derivative of v w.r.t r twice*)

Blockquote

Does this make any sense?

zhk
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