总结
之前不知道如何求一个角的度数,一直卡着,后面知道余玄跟反余玄之间的关系才好做多了,忘得东西太多了
题目链接
/*
____________ ______________ __
/ _________ /\ /_____ _____/\ / /\
/ /\ / / \\ / /\ \ \ / / \
/ / \_____/ / / \__/ / \____\/ / / /
/ / / / / / / / / / / /
/ / / / / / / / / / / /
/ / / / / / / / / / / /
/ /___/____/ / / / / / / /___/________
/____________/ / /__/ / /______________/\
\ \ / \ \ / \ \ \
\____________\/ \__\/ \______________\/
___ ___ ___ __________
/ /\ / /\ / /\ /_______ /\
/ /__\___/ / \ / / \ \ / / \
/____ ____/ / / / / \____/ / /
\ / /\ \ / / / / / / /
\_/ / \___\/ ___ / / / / / /
/ / / / /\ / / / / / /
/ / / / /__\__/ / / / /___/____
/___/ / /___________/ / /___________/\
\ \ / \ \ / \ \ \
\___\/ \___________\/ \___________\/
A CODE OF CBOY
*/
#include<bits/stdc++.h>
//typedef long long ll;
//#define ull unsigned long long
//#define int long long
#define F first
#define S second
#define endl "\n"//<<flush
#define eps 1e-6
#define lowbit(x) (x&(-x))
#define PI acos(-1.0)
#define inf 0x3f3f3f3f
#define MAXN 0x7fffffff
#define INF 0x3f3f3f3f3f3f3f3f
#define pa pair<int,int>
#define ferma(a,b) pow(a,b-2)
#define pb push_back
#define all(x) x.begin(),x.end()
#define memset(a,b) memset(a,b,sizeof(a));
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
#define pi 3.14159265358979
using namespace std;
void file()
{
#ifdef ONLINE_JUDGE
#else
freopen("cin.txt","r",stdin);
// freopen("cout.txt","w",stdout);
#endif
}
signed main()
{
IOS;
//file();
int t;
cin>>t;
while(t--)
{
double s,r;
cin>>s>>r;
if(s>=2*r)
{
printf("%.2f\n",pi*r*r);
}
else if(r>=sqrt(s*s/2))
{
printf("%.2f\n",s*s);
}
else
{
double angle=acos(s/2/r);
double sum=( r*r*angle/2-s/2*r*sin(angle)/2 )*8;
printf("%.2f\n",r*r*pi-sum);
}
}
return 0;
}