Please review the trigonometric functions. We need definitions and basic formulas. A good source for it is Muldowney's notes , which are available at the Math Department (main office, CAB 632) and online. I assume the knowledge of pages 169-177 (till formula 18) of it. Please do also Problems 7.25 -- 7.29, 7.30 (a, b), 7.33 on page 187.