Q 13: If A- 30, verify that:1 - tanAcos 24 1+ tan2 A – InterviewSolution

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Q 13: If A- 30, verify that:1 - tanAcos 24 1+ tan2 A

Answer»

Given,A = 30

LHS: cos 2A= cos 2*30= cos 60 = 1/2

RHS: 1 - tan^2 A/1 + tan^2 A= 1 - tan^2 30/1 + tan^2 30= 1 - (1/sqrt(3))^2 /1 + (1/sqrt(3))^2= (1 - 1/3)/(1 + 1/3)= (2/3)/(4/3)= 2/4= 1/2

LHS = RHS

Hence proved

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