I’ve uploaded a pdf of Solutions to about half the problems in the Cartoon Guide to Calculus. You can either download it or read it in your browser. You should also look at the Errata sheet, which details a number of errors in the early printings of the book. (These links are also on the Calculus page on this site.) I’ve recently sent the publisher a revised electronic file that fixes all the mistakes (and makes minor changes to the problem sets), and as soon as the the corrected edition is in print, I’ll post an update here.