C-09-Q074mediumsingle_mcqWith the same data, cos2θ−sin2θ=?\cos^2\theta - \sin^2\theta = ?cos2θ−sin2θ=?a41841\dfrac{41}{841}84141b129\dfrac{1}{29}291c4129\dfrac{41}{29}2941d111ব্যাখ্যাcos2θ−sin2θ=(2129)2−(2029)2=441−400841=41841\cos^2\theta - \sin^2\theta = \left(\dfrac{21}{29}\right)^2 - \left(\dfrac{20}{29}\right)^2 = \dfrac{441 - 400}{841} = \dfrac{41}{841}cos2θ−sin2θ=(2921)2−(2920)2=841441−400=84141.