Let the equation of two diameters of a circle <img alt="\mathrm{x^{2}+y^{2}-2 x+2 f y+1=0 \text { be } 2 \text { p } x-y=1}" src="/latex-image/?%5Cmathrm%7Bx%5E%7B2%7D+y%5E%7B2%7D-2%20x&am
Let the equation of two diameters of a circle and . Then the slope of the tangent to the hyperbola passing through the centre of the circle is equal to _________.