1.

Tan(A+45) + Tan(A-45) = 2Sec2A

Answer»

TAN(45+A)+tan(45-A) =

= [tan(45)+tanA] / [1-tan45.tanA] + [tan(45)-tanA] / [1+tan45.tanA] =

= (1+tanA) / (1-tanA) + (1-tanA) / (1 + tanA) =

= (1+tanA)^2 / (1-tan^2A) + (1-tanA)^2 / (1 - tan^2A) =

= [(1+tanA)^2 + (1-tanA)^2] / (1-tan^2A) = 2(1+tan^2A) / (1-tan^2A) =

= 2sec2A

LHS=RHS

hope it helps.. regrads


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