Consider the functions and . These are continuous and differentiable for . In this problem we use the Racetrack Principle to show that one of these functions is greater than the other, except at one point where they are equal.

(a) Find a point such that .  

(b) Find the equation of the tangent line to at for the value of that you found in (a).

(c) Based on your work in (a) and (b), what can you say about the derivatives of and ?
for , and
for .

(d) Therefore, the Racetrack Principle gives
for , and
for .

You can earn partial credit on this problem.