cos 2A = cos2 A2 A- sin – InterviewSolution

1.

cos 2A = cos2 A2 A- sin

Answer»

Given A = 30°

LHS: cos 2A= cos 2*30= cos 60°= 1/2

RHS: cos^2 A - sin^2 A= cos^2 30 - sin^2 30= (root(3)/2)^2 - (1/2)^2= 3/4 - 1/4= 2/4 = 1/2

Hence proved

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