Problem Description
Now, we have a function f(x)=Ax2−Bsinx,A≥0,B≥0, here A and B are integer. We want to know minimum x satisfy f(x) = y, and x>=0.
Input
The first line in the input file is an Integer T(1≤T≤500).
The first line of each test case contains two integer A,B(0≤A,B≤103).
Then a line a integer y(−103≤y≤103).
Output
For each test case, output the minimum x. if no such x exists, output “error”.
The answer should accurate to five decimal places.
Sample Input
2
1 0
5
1 1
-2
Sample Output
2.23607
error
