Ответ:(1 - cosy)/(1 + cosy)

Объяснение:(2siny-sin2y)/(2siny+sin2y) =

= (2siny-2siny·cosy)/(2siny+2siny·cosy) =

= 2siny·( 1 - cosy)/(2siny·(1 + cosy)) =

= (1 - cosy)/(1 + cosy)