Let k(x) be the curvature of y=ln(x) at x. Find the limit as x approaches to the positive infinity of k(x). At what point does the curve have maximum curvature? You're supposed to parametrize the graph of ln(x), which I found to be x(t)=(t,ln(t)). And you're not allowed to use the formula with the second derivative, only k(t)=magnitude T'(t)/ magnitude v'(t). I have problem simplifying the formula for T'(t) and k(t).