function Y=sistem(X,par)
%leva stran sistema enacb za veriznico / function that
%returns the right-hand side of the equation for the catenary 
a=X(1);%neznanki a in b / the unknowns a and b
b=X(2);
H=par(1);%visinska razlika /  hight difference
L=par(2);%dolzina vrvi / length of wire
D=par(3);%razpon / distance to be bridged
Y=[a*(cosh(b/a)-cosh((b-D)/a))-H;a*(sinh(b/a)-sinh((b-D)/a))-L];%leva stran enacb 
end