How do you find all solutions if 0 ≤ θ < 2π for #cos 2x cos x − sin 2x sin x = sqrt2/2#?

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How do you find all solutions if 0 ≤ θ < 2π for #cos 2x cos x − sin 2x sin x = sqrt2/2#?

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Answer 1 · 2015-12-06T05:22:20

Solve trig equatiom.

Ans: #+- pi/4#

Explanation:

Apply the trig identity; cos (a + b) = cos a.cos b - sin a.sin b
We get:
#cos (2x + x) = cos 3x = sqrt2/2#
Trig table of special arcs gives -->
#cos 3x = sqrt2/2# --> #arc x = +-pi/4#

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How do you find all solutions if 0 ≤ θ < 2π for #cos 2x cos x − sin 2x sin x = sqrt2/2#?

1 Answer

Explanation:

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