9
QuizMultiple Choice
Trigonometric Sum Identities
Question 9 • Precalculus
Review the incomplete derivation of the cosine sum identity.Step 1Step 2Step 3 Step 4Step 5
Answer
A
Step 3: Step 5: cos(x)cos(y) + sin(x)sin(y)
B
Step 3: Step 5: cos(x)cos(y) – sin(x)sin(y)C
Step 3: Step 5: cos(x)cos(y) + sin(x)sin(y)
D
Step 3: Step 5: cos(x)cos(y) – sin(x)sin(y)