SSC CGL 9 Aug 2015 Shift 2 Paper

tan (90° – θ) = cot θ
tan θ . cot θ = 1
tan 89° = tan (90° – 1°) = cot 1°.
tan 88° = tan (90° – 2°) = cot 2°.
∴ Expression = (tan 1°.tan 89°) (tan 2°.tan 88°) ---- tan 45°
= (tan 1°.cot 1°). (tan 2°.cot 2°) - --- tan 45°
= 1.1 ---- 1 = 1