Ответ:
1) 28 : 7 * 4=16 - девочек
Это сложная функция<br />будет 1/3sin²*(x/3)
ctg(x/3)=cos(x/3)/sin(x/3)
поэтому
f'=(cos'(x/3)*sin(x/3)-sin'(x/3)*cos(x/3))/sin²(x/3)=
(-sin(x/3)*1/3*sin(x/3)-cos(x/3)*cos(x/3)*1/3)/sin²(x/3)=
=-1/3*(sin²(x/3)+cos²(x/3))/sin²(x/3)=-1/(3*sin²(x/3))
80 / 20 = 4, 150 / 50 = 3, 6 / 12 неравно 2
ABC, MBC, DBC, ABM, DBO,
BOD, COM, BOC
1) 25 и 300 НОК(300)
3/25=36/300
17/300=17/300
2) 12, 20 и 60 - НОК(60)
5/12=25/60
1/20=3/60
17/60=17/60
3) 30, 180, 15 НОК(180)
11/30=66/180
19/180=19/180
1/15=12/180