5
QuizMultiple Choice
Trigonometric Double Angle Identities
Question 5 of 10 • 2025-2026 FBISD - Precalculus A (CR)
Consider the derivation of an alternate form of the cosine double angle identity.
Answer
A
In step 1, cos(2x) is equal to cos2(x) + sin2(x).B
In step 2, sin2(x) should have been replaced with 1 + cos2(x).C
In step 3, cos2(x) – 1 – cos2(x) should be cos2(x) – 1 + cos2(x).D
In step 4, 2cos2(x) – 1 should be 1 – 2cos2(x).