MATH SOLVE

4 months ago

Q:
# 1+cos(18x)=A. 2cos^2(9x) B. 2sin^2(9x)C. 2cos^2(18x)D.2sin^2(18x)

Accepted Solution

A:

Answer: AStep-by-step explanation:1 + cos(18x) becomes 1 + cos(9x + 9x) 1 + cos²(9x) - sin²(9x) 1 + cos²(9x) - (1 - cos²(9x)) 1 + cos²(9x) - 1 + cos²(9x) 2 cos²(9x)