Pre-AP Pre-Calculus Chapter 5, Section 3 Sum and Difference Identities 2013 - 2014

Use the given triangle to derive the formulas for sin 𝛼+𝛽 and cos 𝛼+𝛽 1 𝛼 𝛽

Use the given triangle to derive the formulas for sin 𝛼−𝛽 and cos 𝛼−𝛽 1 𝛼 𝛽

Cosine of a Sum or Difference

Sine of a Sum or Difference

Using the Sum/Difference Formulas Write each of the following expressions as the sine or cosine of an angle. sin 22° cos 13° + cos 22° sin 13° cos 𝜋 3 cos 𝜋 4 + sin 𝜋 3 sin 𝜋 4 sin 𝑥 sin 2𝑥 − cos 𝑥 cos 2𝑥

Find the exact value of each expression. sin 105° cos 7𝜋 12 sin 𝜋 12

Find the exact value of each expression. sin 30° cos 60° − cos 30° sin 60° cos 120° cos 45° − sin 120° sin 45°

Let’s Practice #2 Write the expression as the sine, cosine, or tangent of an angle. cos 94° cos 18° + sin 94° sin 18°

Ch 5.3 Homework Pg. 468 – 469, #’s: 1, 6, 14, 17, 20, 31 – 34, 48, 50 11 total problems Gray book: pg. 425 - 426