1. Warm-up:
Simplify:
HW: pages (2-26 EVEN)

2. 15) (sinx + cosx)(sinx – cos) 16) (3sinx + 2)(sinx – 3)
CW Answers: Fundamental Trigonometric Identities 2
1)A
2)A
3)E
4)E
5)A
6)A
7)G
8)B
9)I
10)C
11)D
12)J
13)A
14)A
15) (sinx + cosx)(sinx – cos)
16) (3sinx + 2)(sinx – 3)
17) (tanx – 1)(tan2x + tanx + 1)

3. Verifying Trigonometric Identities
Objective:
Verify trigonometric identities by…
Using the fundamental trigonometric identities
Combining fractions before using identities
Converting to sines and cosines
Working with each side seperately

4. Guidelines for Verifying:
You must have your basic identities memorized!
You should work with the more complicated looking side first. Remember that you can’t move terms from one side to the other or multiply both sides by something.
3)Look for opportunities to factor an expression
4)Typically, you will want to add fractions together, simplify fractions so that they have monomials in the denominator.
5)Look for opportunities to use trigonometric identities to get functions that are the same or that pair up well like sine and cosine, tangent and secant, or cotangent and cosecant.
6)You may want to multiply the numerators and denominators of fractions in order to create the difference of two squares.
7)If nothing comes to mind just try something! It may lead somewhere or it might not but either way you will gain some insight about how to verify the identity.

5. Example 1: Verifying a Trig Identity

6. Example 2: Verifyng the identity by
Combining Fractions before Using Identities

7. Example 3: Verifying a Trig Identity

8. Example 4: Verifying the Identity by Converting to Sines and Cosines

9. Example 5: Verifying Trig Identities
work with more complicated side first!

10. Example 6: Verify the identity
working with each side seperately

11. Example 7: Two Examples for Calculus Verify the identity.
A common procedure in calculus is to rewrite powers of trigonometric functions as more complicated sums of products of trigonometric functions
a) b)

12. Sneedlegrit:
Verify:
HW: pages (2-26 EVEN)