function xroot = RaiQuad(d,e,f)
  a=single(d); b=single(e); c=single(f);
	disc = sqrt( b^2 - 4 * a *c );
	xroot(1) = -b - disc;
	xroot(2) = -b + disc;
	xroot = .5 * xroot;
endfunction

RaiQuad(2,4,1)

RaiQuad(1,-1e4-1e-4,1)

