SSC CGL 9 Aug 2015 Shift 1 Paper

tan 86° = cot (90° – 86°) = cot 4°.
tan 47° = cot (90° – 47°) = cot 43°
∴ (tan 4°. tan 86°) (tan 43°.tan 47°) = (tan 4° : cot 4°) (tan 43°.cot 43°)
= 1
(Since tan θ . cot θ = 1)