NDA Mathematics Question (2026) — Solution

Step-by-step solution

Let = ^ -1 1 2 , which implies = 1 2 . We need to evaluate (2 - 4 ). First, calculate (2 ) using the double angle formula: (2 ) = 2 1 - ^2 = 2 ( 1 2 ) 1 - ( 1 2 )^2 = 1 1 - 1 4 = 4 3 Now, apply the tangent subtraction formula: (2 - 4 ) = (2 ) - ( 4 ) 1 + (2 ) ( 4 ) Substitute (2 ) = 4 3 and ( 4 ) = 1: (2 - 4 ) = 4 3 - 1 1 + 4 3 (1) = 1 3 7 3 = 1 7 Answer: 1 7