Calculus 4.2 Critical Points, First Derivative Test

Once again I explain the first derivative test and show you two ways to use it to determine maxima and minima. I do several examples including 7e and #15 which is a question that requires you to find values for a, b, c, and d of a quartic function given two critical points that have horizontal tangents (which just means that they have ZERO slope at those points) It's a tricky question so it is a good one for you to try on your own ... struggle a little before you see how it is done and also try it again on your own until you understand the subtleties of the question.