1. The problem statement, all variables and given/known data hmmm....I know this can't be hard. i am given B^j Nj =(tau) I need B^j=N^J (tau) 2. Relevant equations 3. The attempt at a solution Our professor just kinda left us hanging, telling us we should be able to figure the rest out, and I have no idea where to go. I can't multiply by N^j for B^j, if i bring up the j on N with gij, i get gij B^j N^j =(tau). This is my first time doing this, and am about to hit up the library, teacher left for the next few weeks and this is bugging me like no other. EDIT: Nevermind. i mis-copied something. turns out i am just proving the frenet serret formulas.