Let d >1 and In be a sequence of points with x1 > vd. We consider the function f (x) = x2 d. We denote by xn+1 the intersect of the tangent line of the function f at (xn, x- d) and x-axis. (1) Show that xn > Vd. (2) Show that x + d Xn+1 = 2xn (3) Show that Xn - V Xn+1 Vd < (4) Show that lim xn