Respuesta :

Answer:

Step-by-step explanation: 2cos3 theta=1. Cos 3theta=1/2. Since cos 60°= 1/2. Therefore cos 3theta=cos 60°. Theta=20°.

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2(cos 3theta) = 1
Cos 3theta = 1/2 = cos(60)
Theta = 60/3 = 20