No links Q 17 . If tan y 2 = a b , then what is the value of a sin y + cos y ? A ) 0 B ) 1 C ) a D ) b Share with your friends Share 1 Abhishek Jha answered this tany2=ab ...(i)⇒cosy2=ba2+b2 ...(ii)Now we have;asiny+bcosy=2asiny2cosy2+bcos2y2-sin2y2 {Since sin2θ=2sinθcosθ and cos2θ=cos2θ-sin2θ}=cos2y22asiny2cosy2cos2y2+bcos2y2-sin2y2cos2y2 {Multiplying and dividing by cos2y2}=cos2y22atany2+b1-tan2y2=ba2+b222a×ab+b1-a2b2 {using (i) and (ii)}=b2a2+b22a2b+bb2-a2b2=b2a2+b22a2b+b2-a2b=b2a2+b2×a2+b2b=b Regards 0 View Full Answer