C-09-Q102mediumsingle_mcqsinA1−cosA+1−cosAsinA=?\dfrac{\sin A}{1 - \cos A} + \dfrac{1 - \cos A}{\sin A} = ?1−cosAsinA+sinA1−cosA=?a2cosecA2\operatorname{cosec} A2cosecAb2secA2\sec A2secAc2tanA2\tan A2tanAd2cotA2\cot A2cotAব্যাখ্যাOver a common denominator the numerator is sin2A+(1−cosA)2=sin2A+1−2cosA+cos2A=2−2cosA=2(1−cosA)\sin^2 A + (1-\cos A)^2 = \sin^2 A + 1 - 2\cos A + \cos^2 A = 2 - 2\cos A = 2(1-\cos A)sin2A+(1−cosA)2=sin2A+1−2cosA+cos2A=2−2cosA=2(1−cosA), giving 2(1−cosA)sinA(1−cosA)=2sinA=2cosecA\dfrac{2(1-\cos A)}{\sin A(1-\cos A)} = \dfrac{2}{\sin A} = 2\operatorname{cosec} AsinA(1−cosA)2(1−cosA)=sinA2=2cosecA.