Question

Sinx + siny/ cosx + cosy

Answer 1

(sin x + sin y) / (cos x + cos y)

= 2 sin [(x+y)/2] cos[(x–y) /2] ÷ 2 cos [(x+y)/2] cos[(x–y) /2]

= sin [(x+y)/2] ÷ cos [(x+y)/2]

= tan [(x+y)/2]