Q19 of 123 Page 9

Mark the Correct alternative in the following:

If tan (/4 + x) + tan (/4 – x) = λ sec 2x, then


Given equation is



Let us consider LHS



[ using the formulae and ]



[ the value of tan 45° = 1 ]







[using the formulae cos 2x = cos2 x – sin2 x and cos2 x + sin2 x = 1]



= 2 sec 2x


Now comparing with the LHS with RHS



From here we can clearly say that the answer is option D.

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