Prove the following: cosA / 1 - sinA = tan (45 + A/2) Share with your friends Share 42 Prasanta answered this L.H.S=cos A1-sin A =cos 2A21-sin 2A2 =cos2A2-sin2A2sin2A2+cos2A2+2sinA2cosA2 =cosA2+sinA2cosA2-sinA2cosA2+sinA22 =cosA2-sinA2cosA2+sinA2 =1-tanA21+tanA2 (Dividing both numerator and denominator by cosA2) =tan45°+A =R.H.S Hence Proved. 18 View Full Answer