1. October 27, 2011 At the end of today, you will be able to : Apply trig identities to solve word problems. Warm-up: Prepare for the Unit Circle Quiz. When you are done with the quiz start CW 4.2 Pg. 299 #5-18, this will be graded. I will collect it in 15 minutes.

2. “Yo, Ms. PD! I was wondering why the x and y-coordinates end up being the cosine and sine of the angle. Is it just a coincidence?”

3. How we get those points on the unit circle… Let’s concentrate on the 1 st quadrant. Start with the 45-45-90 triangle 1 30-60-90 triangle 1 60° 45°

4. Here’s a little R&B to help make more sense out of it…

5. Why is the cosine of 90° 0?

6. Lesson 4.3 Right Triangle Trig HW 4.3 Pg. 308 #2, 3, 17-26

7. Example 1: Evaluating Trig Functions Find the exact value of six trig functions of the angle θ shown in the figure. (Use the Pythagorean Theorem to find the third side.) 41 9 Pythagorean Theorem a 2 + b 2 = c 2 9 2 + b 2 = 41 2 40 θ HW #3

8. How to enter trig functions in your calculator Make sure your calculator is in the correct angle mode! Include parentheses around fractions. How would you try to find the angle if you were given the value of the trig function? Enter:

9. Fundamental Trig Identities Reciprocal Identities Quotient Identities Pythagorean Identities sin 2 θ + cos 2 θ = 1 1+ tan 2 θ = sec 2 θ 1+ cot 2 θ = csc 2 θ