On the smooth manifold $M$, suppose $v$ is a tangent vector to $x$. How can one show that for a differentiable function $f$ on $M$, non zero in a neighborhood of $x$, $v(\frac{1}{f})$= $- \frac{v(f)}{f(x)²}$
I just began studying tangent vector on smooth manifold and besides using Leibniz rule and linearity of $v$ I have no idea how to proceed