Covariant derivative of ▽_{X}(e^{-f}), where X is a vector field over a manifold and

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Covariant derivative of ▽_{X}(e^{-f}), where X is a vector field over a manifold and

I want to determine the covariant derivative Je veut déterminer la derivée covariante ▽_{X}(e^{-f}), where X is a vector field over a manifold and f is a C^{∞} function

Is it: ▽_{X}(e^{-f})=e^{-f}<▽f,X>, or another similar relation?