Задачка по физике на бросание шарика

X=v*cos(a+b)*t
y=v*sin(a+b)*t-g*t^2/2
y=x*tg(a)
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x=v*cos(a+b)*t
y=x*tg(a)
v*sin(a+b)*t-g*t^2/2=v*cos(a+b)*t*tg(a)
v*sin(a+b)-g*t/2=v*cos(a+b)*tg(a)
t=2v/g*(sin(a+b)-cos(a+b)*tg(a))=2v/g*sin(b)/cos(a)
v=t*g/2*cos(a)/sin(b)

x=v*cos(a+b)*t=g*t^2/2*cos(a)*cos(a+b)/sin(b)
L=x/cos(a) = g*t^2/2*cos(a+b)/sin(b)=10*2^2/2*cos(18+36)/sin(36) м =
=10*2^2/2*cos(54)/sin(36) м =10*2^2/2 м = 20 м