%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% function f(T)
% Return: 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function z=f(T,Print)

global X1;
global Y1;
global X2;
global Y2;
global P1;
global P2;
global P3;
global L1;
global L2;
global L3;
global R;

MYCOS = (1 - T^2) / (1 + T^2);
MYSIN = (2 * T) / (1 + T^2);

A2 = L3 * MYCOS - X1;
B2 = L3 * MYSIN;
A3 = L2 * (MYCOS * cos(R) - MYSIN * sin(R)) - X2;
B3 = L2 * (MYCOS * sin(R) + MYSIN * cos(R)) - Y2;

x = (B3 * (P2^2 - P1^2 - A2^2 - B2^2) - B2 * (P3^2 - P1^2 - A3^2 - B3^2)) / ( 2 * (A2 * B3 - B2 * A3));
y = (-A3 * (P2^2 - P1^2 - A2^2 - B2^2) + A2 * (P3^2 - P1^2 - A3^2 -B3^2)) / ( 2 * (A2 * B3 - B2 * A3));

z = x^2 + y^2 - P1^2;

if(nargin>1)
  fprintf(1,'x=%16.10f, y=%16.10f \n',x,y);
end

end