2016 Multi-University Training Contest 3 1010 Teacher Bo(数学)
2016-08-01 11:48
399 查看
题目链接:HDU5671
现在你在(0,a)这个点,要到原点去,速度为V1,速度方向保持始终指向原点,问所花的时间。
这样可分别对x和y方向列方程
dydt=v1sinθ dxdt=v2−v1cosθ
积分得
0−a=∫T0v1sinθdt 0−0=v2T−∫T0v1cosθdt
然后做三角代换得
T=av1v21−v22
当v1<v2 时,无解
当v1=v2时,仅当a=0时有解为0;
简单题意
有一条X轴正向的河流,水流速度为V2现在你在(0,a)这个点,要到原点去,速度为V1,速度方向保持始终指向原点,问所花的时间。
思路
把问题转化一下,认为是原点以V2的速度左移,你要去追原点,这样可分别对x和y方向列方程
dydt=v1sinθ dxdt=v2−v1cosθ
积分得
0−a=∫T0v1sinθdt 0−0=v2T−∫T0v1cosθdt
然后做三角代换得
T=av1v21−v22
当v1<v2 时,无解
当v1=v2时,仅当a=0时有解为0;
代码
#include <bits/stdc++.h> using namespace std; int main(){ double a,v1,v2; while(~scanf("%lf %lf %lf",&a, &v1, &v2)){ if(a == 0) {puts("0");continue;} if(v1 <= v2){puts("Infinity");continue;} printf("%.10f\n",a*v1/(v1*v1-v2*v2)); } }
相关文章推荐
- 2016 Multi-University Training Contest 3 hdu 5762 Teacher Bo【计算几何】
- 2016 Multi-University Training Contest 3-1011.Teacher Bo,暴力!
- 2016 Multi-University Training Contest 3 1011 Teacher Bo
- hdu5753 2016 Multi-University Training Contest 3 Permutation Bo 解题报告
- 2016 Multi-University Training Contest 7 1002 Balls and Boxes (数学)
- 2016 Multi-University Training Contest 3 hdu 5753 Permutation Bo【打表+递推】
- 数据结构 ( 优先队列&&栈 )——HDU 5818 ( 2016 Multi-University Training Contest 7 1010 )
- 2016 Multi-University Training Contest 7 1010 Joint Stacks (模拟)
- HDU5738 2016 Multi-University Training Contest 2 (组合数学+极角排序)
- hdu 5753 Permutation Bo(2016 Multi-University Training Contest 3——组合)
- hdu 4968 Just a Joke 数学(积分) 2014 Multi-University Training Contest 9-1010
- 2016 Multi-University Training Contest 2 1011 Keep On Movin (简单数学)
- hdu5755 2016 Multi-University Training Contest 3 Gambler Bo 解题报告
- 2016 Multi-University Training Contest 3 1001 Sqrt Bo
- hdu 5810 Balls and Boxes(2016 Multi-University Training Contest 7——数学题)
- hdu5754 2016 Multi-University Training Contest 3 Life Winner Bo 解题报告
- 2016 Multi-University Training Contest 4 1010 The All-purpose Zero(变形LIS)
- 数学——Acperience ( HDU 5734) ( 2016 Multi-University Training Contest 2 1001 )
- 2016 Multi-University Training Contest 2 1001 Acperience (简单数学)
- 2016 Multi-University Training Contest 3 1001 Sqrt Bo