Упростите выражение (cos2t/cost+sint) - cost; tg (-t) * cost-sin (4 П-t)

cos2t / (cost+sint) - cost = (cos²t-sin²t) / (cost+sint) - cost=

= (cost-sint) (cost+sint) / (cost+sint) - cost=cost-sint-cost=-sint

tg (-t) * cost-sin (4π-t) = - sint/cost * cost - (-sint) = - sint+sint=0