- #1
binbagsss
- 1,259
- 11
Homework Statement
Hi
I am looking at part a).
Homework Equations
below
The Attempt at a Solution
I can follow the solution once I agree that ## A^u U_u =0 ##. However I don't understand this.
So in terms of the notation ( ) brackets denote the symmetrized summation and the [ ] the antisymmetrized, both come with a factor of 1/2, for a 2 indices tensors.
So I agree with the second equality if I were to ignore the parentheses, and I agree that the covariant derivative acting on 1 is of course zero for the last equality.
But I thought ##A^u## is such that the covariant derivative acts on the ##U^v## in that expression and that is it, once you multiply it by another vector eg ##A^u V^v ## the covariant derivative does not act on ##V^v ##, it does not act on everything to the right side? So I don't understand how we've changeed the parentheses as in the second equality (solution here: )
Thanks