Let ${\mathbb{H}}^n$ the $n$-dimensional hyperbolic space, $$ {\mathbb{H}}^n = \{(x_0 , x_1 , \ldots , x_n) \in {\mathbb{R}}^{n + 1} : - x_0^2 + \sum_{i = 1}^n x_i^2 = - 1 , x_0 > 0\}. $$ Then we have a bilinear and simetric form in ${\mathbb{H}}^n$ given by $$ \langle \langle (v_0 , v_1 , \ldots , v_n) , (w_0 , w_1 , \ldots , w_n) \rangle \rangle = -v_0 w_0 + \sum_{i = 1}^n v_i w_i. $$ I have to check that $T_p {\mathbb{H}}^n = \{v \in {\mathbb{R}}^{n + 1} \langle \langle v , p \rangle \rangle = 0\}$ for all $p \in {\mathbb{H}}^n$, but I have no idea how to show it.
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I think you are looking for Prop 1.3 here: https://montgomery.math.ucsc.edu/classes/mfds/lect2_06.pdf – preferred_anon Feb 21 '21 at 14:57
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Hint: If $\gamma$ is a curve in $\ct H^n$ with $\gamma(0)=p$ then $\frac d{dt}\langle\gamma(t),\gamma(t)\rangle=0$. – Berci Feb 21 '21 at 15:10
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What’s the general definition of $T_pM$ you have to use? – Deane Feb 21 '21 at 16:15