uva 358

數學問題，二分法即可

記得精度問題

//====================================================================||
//                                                                    ||
//                                                                    ||
//                         Author : GCA                               ||
//                  6AE7EE02212D47DAD26C32C0FE829006                  ||
//====================================================================||
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
using namespace std;
#ifdef ONLINE_JUDGE
#define ll "%lld"
#else
#define ll "%I64d"
#endif
typedef unsigned int uint;
typedef long long int Int;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\n")
#define I_de(x,n)for(int i=0;i<n;i++)printf("%d ",x[i]);Pln()
#define De(x)printf(#x"%d\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\
    printf("%d ",dp[htx][hty]);}Pln();}
#define M 55
#define PII pair<int,int>
#define PB push_back
#define oo INT_MAX
#define Set_oo 0x3f
#define Is_debug true
#define debug(...) if(Is_debug)printf("DEBUG: "),printf(__VA_ARGS__)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define eps 1e-9
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
int min3(int x,int y,int z){
    int tmp=min(x,y);
    return min(tmp,z);
}
int max3(int x,int y,int z){
    int tmp=max(x,y);
    return max(tmp,z);
}
double r,p;
double pi=3.14159;

inline double sq(double a){return a*a;}
double cal(double cr){
    double da=acos(1-sq(cr)/(2*sq(r)));
    double ca=acos(cr/(2*r));
    double ans=sq(r)*(da-sin(da))+sq(cr)*ca;
//    debug("%lf %lf %lf %lf %lf\n",da,ca,squ,daa,caa);
    return ans;
}
int main() {
    ios_base::sync_with_stdio(0);
    int test;
    scanf("%d",&test);
    while(test--){
        scanf("%lf%lf",&r,&p);
        double rr=2*r;
        double l=0;
        double a=r*r*pi*p;
        while(xdy(rr,l)){
            double m=(rr+l)/2;
            if(cal(m)>a)rr=m;
            else l=m;
        }
        printf("R = %.0f, P = %.2f, Rope = %.2f\n",r,p,rr);
        if(test)Pln();
    }

















}