If a rectangular hyperbola \((x-1)(y-2)=4\) cuts a circle \(x^2+y^2+2 g x+2 f y+c=0\) at points \((3,4),(5,3),(2,6)\) and \((-1,0)\), then the value of \((g+f)\) is equal to
For the ellipse \(\frac{x^2}{a_n^2} + \frac{y^2}{b_n^2} = 1\), the tangent at point \((x_1, y_1)\) is \(T = S_1\), i.e., \(\frac{xx_1}{a_n^2} + \frac{yy_1}{b_n^2} = \frac{x_1^2}{a_n^2} + \frac{y_1^2}{b_n^2}\). Given that \(b_n^2 x_1 = a_n^2 y_1\) and the eccentricity \(e = \frac{\sqrt{5}-1}{2}\), find the relation between \(x_1\) and \(y_1\).