Use gradients to find the equation of the line tangent to the hyperbola x - y = 9 at the point (5, 4). (b) Use gradients to find the equation of the line tangent to the hyperbola x - y = 9 at an arbitrary point (x0, yo) on the hyperbola. (c) Show that as to approaches infinity and yo> 0, the slope of the the line tangent to the hyperbola approaches 1 and that as xo approaches infinity and yo < 0, the slope, approaches -1. 62 (d) Show that the slopes of the tangent lines of a general horizontal hyperbola (h) (y-k) = 1 at points (xo, yo) on the hyperbola, approach b/a as xo approaches infinity and yo> 0 and approach -b/a as to approaches infinity and yo < 0.