i have to find the jacobi fields of the follwoing curve's
$\gamma_1:\Bbb R\to \Bbb R^n,t\to p+tX,$ where p, $X\in \Bbb R^n$
$\gamma_2:\Bbb R\to \Bbb S^n \subset \Bbb R^{n+1},t\to p*cos(t)+sin(t)X,$ where $ p \in \Bbb S^2$, $X\in T_p\Bbb S^n, |X| =1$
So i know a vector field $Y \in Γ(γ^∗TM)$ is a jacobi field iff its satisfies $Y''+R(Y,γ')γ'=0$.
Now for $\gamma_1$ i got that $Y''=0$ so $Y(t)=V+tW$ for parallel vector fields V, W along γ (constant) but i'm a bit lost for $\gamma_2$.