Lesson 5.4Sum and Difference Formulas

Warmup: Can you find sin 750 without your calculator?

Sum & Difference Formulas

vuvuvu

vuvuvu

uvvuvu

uvvuvu

sinsincoscoscos

cossincoscoscos

cossincossinsin

cossincossinsin

Notice the

difference between sine and cosine!

Use these formulas to change the angle to a combination of angles from the unit circle:

90

60

45

30

2

3

4

6

From our warmup: 3045sin75sin

Example: Evaluate12

5cos

We can use these formulas to verify and solve trigonometric problems:

Example: Verify xx sin3sin

Example: Solve 14

cos4

cos

xx

Problems Set 5.4