C-09-Q053mediumsingle_mcq1+cot2θ=?1 + \cot^2\theta = ?1+cot2θ=?asec2θ\sec^2\thetasec2θbcosec2θ\operatorname{cosec}^2\thetacosec2θctan2θ\tan^2\thetatan2θdsin2θ\sin^2\thetasin2θব্যাখ্যাDividing sin2θ+cos2θ=1\sin^2\theta + \cos^2\theta = 1sin2θ+cos2θ=1 by sin2θ\sin^2\thetasin2θ gives 1+cot2θ=cosec2θ1 + \cot^2\theta = \operatorname{cosec}^2\theta1+cot2θ=cosec2θ. This is the third Pythagorean identity.