A University of Rochester student decided to depart from Earth after his graduation to find work on Mars. Before building a shuttle, he conducted careful calculations. A model for the velocity of the shuttle, from liftoff at t = 0 s until the solid rocket boosters were jettisoned at t = 79.2 s, is given by v(t)=0.001397167t3−0.080965t2+16.02t−039 (in feet per second). Using this model, estimate the absolute maximum value and absolute minimum value (I found this through using Wolfram Alpha I don't understand how I get it though which is a problem) of the acceleration of the shuttle between liftoff and the jettisoning of the boosters. I got the derivative to be v'(t)= 0.004191201t2-0.16193t+16.02 I imagine that I would have to find the critical points of this to get the max and min So I used the quadriatic formula but I am getting imaginary numbers when I do this so I am having trouble coming up with the absolute maximum and minimum any help would be appreciated.