Originally Posted by

**MarkFL2** In order to apply differentiation (as your topic title suggests) you need to equate the first derivative of the profit function to zero to find values of x (critical values) where extrema may occur. Once you have found the critical value(s), you should then employ either the first or second derivative test to determine those that occur at maxima.

Since the profit function is parabolic, and the coefficient of the squared term is negative, how many and what type of extrema should you expect to find?