Chapter 1.5, Problem 2SA

Plot $f\left(\theta \right)$ on $\left[-\pi ,\pi \right]$ . You may use the @ symbol as described in Appendix B.5 to assign a function handle to your function file in the plotting command. You may also need to precede arithmetic operations with the "." character to vectorize the operations, as explained in Appendix B.2. As a check of your work, there should be roots at $\pm \pi /4$ .