Chapter 4.4, Problem 158E

For the following exercises, graph the functions on a calculator and draw the secant line that connects the endpoints. Estimate the number of points c such that

   $f\text{'}\left(c\right)\left(b-a\right)=f\left(b\right)-f\left(a\right)$

158. [T] $y=\tan \left(\frac{\pi }{4}x\right)over\left[-\frac{3}{2},\frac{3}{2}\right]$