Question

sin A/1+cos A =tan A /2

Answer 1

sinA = 2sin(A/2)cos(A/2)
cosA = 2cos^2 (A/2) - 1

sinA / (1+cosA) = sin(A/2) / cos(A/2) = tan(A/2)

Answer 2

sin A = 2 sin (A/2) cos (A/2) 
1 + cos A = 2 cos^2 (A/2) 

Therefore, 
sin A / ( 1 + cos A ) 
=2 sin (A/2) cos (A/2) / 2 cos^2 (A/2) 
= tan (A/2)