1 #include <cstdio> 2 #include <cstring> 3 #include <cmath> 4 #include <algorithm> 5 #define maxn 2000 6 using namespace std; 7 const double pi=acos(-1.0); 8 9 10 int main() 11 { 12 double v,a,k; 13 scanf("%lf%lf%lf",&v,&a,&k); 14 double ans=0; 15 a=a*pi/180; 16 while(1) 17 { 18 if(v<0.01) break; 19 ans+=(2*v*cos(a)*v*sin(a))/10.0; 20 double ek=0.5*v*v; 21 ek=ek/k; 22 v=sqrt(ek*2.0); 23 } 24 printf("%.2lf\n",ans); 25 return 0; 26 }