<p>Oh shoot, sorry I forgot another condition. a<em>b</em>c =1. intellec7, you have the right idea. but a,b,c > 1 is not necessarily true. But with this new condition take a look at what happens with f'(x) in the case when t = 0. I like this problem because it's slightly different from what you're typically asked to show for a function on the free response.</p>