C-09-Q113mediumsingle_mcq(1+cosA)(1−cosA)=?(1 + \cos A)(1 - \cos A) = ?(1+cosA)(1−cosA)=?asin2A\sin^2 Asin2Abtan2A\tan^2 Atan2Acব্যাখ্যাExpanding gives the difference of squares 1−cos2A1-\cos^2 A1−cos2A, which by the Pythagorean identity equals sin2A\sin^2 Asin2A.