deletions | additions       diff --git a/vec_a_t_Delta_t__.tex b/vec_a_t_Delta_t__.tex  index edb4b46..4cdaf43 100644  --- a/vec_a_t_Delta_t__.tex  +++ b/vec_a_t_Delta_t__.tex 
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$$(\vec a(t) + \vec  a(t+\Delta t)+ t))\Delta t^2=  \veca(t))\Delta t^2=\vec x(t)-\vec  x(t-\Delta t)+\vec x(t+\Delta t)-\vec{x}(t+2 t) - \vec x(t)  + \vec{x}(t+2  \Delta t)$$ t) - \vec x(t+\Delta t) $$