1. The problem statement, all variables and given/known data I have to prove two of the curvature formulas. The first one is (V X A) / l V3l The other one is a(t) * N(t) / l V(t) I2 2. Relevant equations I have a hint from my professor, but it is all confusing. I need a youtube video or something to get started on these. 3. The attempt at a solution I used the a(t) = at *T + an*N to get the first part, but now I am stuck on the making it into the form of V X A. The I have no idea how I would get it over the cube of the speed.