Write the expression as the sine or cosine of an...
Transcript of Write the expression as the sine or cosine of an...
PCLesson 54(a)_notes.notebook November 16, 2015
5.4(a) Sum and Difference Formulas
Students will be able to use sum and difference formulas to evaluate trigonometric functions, verify trigonometric identities, and solve trigonometric equations.
sin(A ± B) = sinA cosB ± cosA sinB
sin(A + B) = sinA cosB + cosA sinB
sin(A B) = sinA cosB cosA sinB
cos(A ± B) = cosA cosB sinA sinB
cos(A + B) = cosA cosB sinA sinB
cos(A B) = cosA cosB + sinA sinB
Example
Find the exact value of each expression.
1. (a) sin( + ) (b) sin + sin 2π 3
5π 6
2π 3
5π 6
2. (a) cos( ) (b) cos cos 7π 6
π 3
7π 6
π 3
PCLesson 54(a)_notes.notebook November 16, 2015
Example
Find the exact values of the sine and cosine of the angle.
17π 12
7π 6
π 4
= +
Example
Write the expression as the sine or cosine of an angle.
(a) sin 110o cos 80o + cos 110o sin 80o
(b) cos cos sin sin 4π 9
4π 9
π 8
π 8
PCLesson 54(a)_notes.notebook November 16, 2015
Homework
P381: 11, 13, 31, 3541(odd)
Example
Find the exact value of the expression.
(a) cos cos sin sin
(b) cos 120o cos 30o + sin 120o sin 30o
π 16
3π 16
3π 16
π 16