1. The problem statement, all variables and given/known data A particle moves so that its pos. vector is gn by r = cos wt i+sin wt j. show that the velocity v of the particle is perpendicular to and that rxv is a constant vector. 2. Relevant equations 3. The attempt at a solution I've tried working this out assuming [B]v[/B] = xi + y j + zk and proceeding with the vector product, but i'm not able to solve for sin wt = 1. (rxv / mod r mod v) Actually this problem is under the chapter differential vector calculus, but i dont know if perpendicularity can be found usin DVC. Please help.