1. The problem statement, all variables and given/known data If r(t) = −3t2i+2tj+(t2 −3t)k gives the position of a particle at time t, find the time t at which the speed of the particle is minimized. 2. Relevant equations 3. The attempt at a solution i know for minimization and maximization, you find the derivative and solve for the variable and see which values produces a largest or smallest value when plugged into the original equation right? so, since this is asking for speed, would it be right to find the deriv of this (v(t)) and find the absolute value of it (|(v(t)| = s(t)) then find the derivative of s(t) and solve for t? and just a side question but, s(t) is just the magnitude of the velocity vector right?