Ctga = 4/3
Ctg2a = ( 1-tg^2a) / 2tga
ctg2a = (1 - 16/9) / (2 × 4/3) = - (7×3) / (9×8) = 7/24
Ответ:
Объяснение:
((2у+1)/(y+3)^2 -(y-2)/(y(y+3))×y(y^2 -9)/(y^2 +6)=(2y^2 +y-y^2 -y+6)/(y(y+3)^2)×y(y-3)(y+3)/(y^2 +6)=(y^2+6)/(y+3) ×(y-3)/(y^2 +6)=(y-3)/(y+3)