January 30, 2017
Aim 64: How do we use the sum and difference of angle formulas? Do Now: Determine the exact values for the following:
a. sin 30o b. sin 45o c. sin 60o d. sin 75o
Sum & Difference of Angles
Along with the basic and Pythagorean trigonometric identities, there are actually many more. Today, we will work with the sum & difference identities for sine and cosine. The following formulas we will use and refer to: Ex 1) Find an expression for the exact value of sin (75o) in simplest radical form. Ex 2) Determine the exact value of cos (15o) in simplest radical form. January 30, 2017
3) If sin A = and angle A lies in quadrant II, and cos B =
and angle B lies in quadrant I, find a) sin (A ­ B)
b) cos (A + B)
4) Evaluate (sin 42ocos 12o ­ cos 42osin 12o) without a calculator.
January 30, 2017
5) 6) 7) January 30, 2017
#16
January 30, 2017