4пи/3=4*180/3=240
Математика
y(-x)=1-cos(-x)/1+cos(-x)=1-cosx/1+cosx=y(x) четная
y(-x)=cos(-x-pi/2)-(-x)^2=cos(x+pi/2)-x^2=-cos(x-pi/2)-x^2
sqrt(1-2sinx)
-1<=sinx<=1
-2<=2sin2x<=2
3>=1-2sinx>=-1
[-1;3]
1) s1 / s2 = 1,5 * t2 * v1 / t2 * 2 * v1;
2) s1 / s2 = 1,5 / 2;
3) s1 / s2 = 3/4.
Ответ: 3/4.
25*7/15:7/9 = 25* 7/15*9/7= 25*0,6 = 15