Question 1: A parts assembler works the 3:00 P.M.-to-11:00 P.M. shift after having spent the early part of the day at another job. The number of assemblies N the worker has completed after t hours is given by N=-.10t3+.50t2+7.86t At what time is the worker assembling parts at the greatest rate?
Question 2: Find the critical number(s) of the function. f(x)=4x/(x2+9)