How Do You Derive the Geodesic Equation?

PhysicistFTW
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1. A straight line in flat space may be defined by the equation:
(when I use the ^ symbol in this case it means like upper subscript not to the power)


(U^v)(d/dx^v)(U^u)=0


(U^u=dx^u/ds)

derive the geodesic equation.

Please help I'm completely clueless all I can really see to do is mix the two equations but that doesn't really show me anything more clearly, any help would be greatly appreciated.


 
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also it says to make the equation covariant if that helps
 

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