# Trigonometry

posted by Sammy

Solve:
2 cos[x-ð/8]-sqrt2=0

1. Reiny

2 cos(x - π/8) - √2 = 0
cos (x-π/8) = √2/2
we know cos π/4 = √2/2 , so
x - π/8 = π/4 or x-π/8 = 7π/4
x = 3π/8 or x = 15π/8 ( 67.5° or 337.5°)

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