import java.util.*;
import java.text.*;
public class Main{
public static void main(String [] args)
{
final double eps = 1e-10;
final double g = 9.8;
Scanner cin = new Scanner ( System.in );
int test = cin.nextInt();
double x , y , v , delt , t ;
DecimalFormat ctrl = new DecimalFormat ( "0.000000");
while ( test > 0 )
{
test -- ;
x = cin.nextDouble();
y = cin.nextDouble();
v = cin.nextDouble();
t = g * x *x / ( v * v );
delt = x * x - t * ( t + 2 * y );
if ( delt > - eps )
{
double rel = (Math.atan((x-Math.sqrt( delt ))/t));
System.out.println(ctrl.format(rel));
}
else
{
System.out.println("-1");
}
}
}
}
posted on 2009-08-18 19:31
Huicpc217 阅读(128)
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