知识点:Java计算sin,使用Math.sin(),参数是弧度制,需要用Math.PI来转换
Double保留小数位可以使用 String.format("%.3f", number)
http://blog.youkuaiyun.com/ming1683/article/details/3195058
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
while(s.hasNext()){
int count = s.nextInt();
for(int i = 0; i < count; i++){
double R = s.nextDouble();
int n = s.nextInt();
double tmp = Math.sin(Math.PI/n);
System.out.println("Scenario #"+(i+1)+":");
System.out.println(String.format("%.3f", R * tmp/(1 + tmp)));
System.out.println();
}
}
}
}