Cos 2x cos x − sin 2x sin x = radical 3 /2

Mathematics

1 answer:

9966 [12]4 years ago

6 0

Cos2x.cosx - sin2x.sinx = cos(2x+x)

cos(2x+x) = cos(3x) = (√3)/2

cos⁻¹ (√3/2) = 30°, so x =30/3 = 10°

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