1. Section 7-3 The Sine and Cosine Functions Objective: To use the definition of sine and cosine to find values of these functions and to solve simple trigonometric equations.

2. The Sine and Cosine Function We define the sine of ѳ denoted by Sin ѳ by We define the Cosine of ѳ denoted by Cos ѳ by

3. Example 1 If the terminal ray of an angle ѳ in standard position passes through (-3,2) find Sin ѳ and Cos ѳ. Use the equation x 2 +y 2 = r 2 with x =-3 and y= 2 (-3) 2 + (2) 2 = 9 + 4 = 13 So r2 = 13 and r = √13 Thus And

4. Example 2 If is a fourth quarter angle and Since Find x

5. Signs of Sine and Cosine The Signs of the Trig functions are as follows (1,0)(-1,0) (0,-1) (0,1)

6. Example 3 Find the Sin and Cosine given the following points (0,1) (-10,-8)

7. Homework(1-23 odd) Pgs. 272 Day 2: (24-43)pg.273