Chapter 4.4, Problem 185E

For the following exercises, use a calculator to graph the function over the interval [a, b] and graph the secant line from a to b. Use the calculator to estimate all values of c as guaranteed by the Mean Value Theorem. Then, find the exact value of c, if possible, or write the final equation and use a calculator to estimate to four digits.

185. [T] $y=\tan \left(\pi x\right)\text{over}\left[-\frac{1}{4},\frac{1}{4}\right]$