**Interesting calculation**

An interesting back of the envelope calculation: UC Irvine is using the differential equations book as standard, that’s a couple of hundred students every quarter, and there are at least a few other places with large and small lectures using the book. A reasonable estimate at the current adoption, there are at least 1000 students every year who use the book. I recently checked on amazon how much does Boyce-DiPrima cost: the new edition is $184 (Yaikes!). It costs $110 just to rent for a semester (a used version was $165). That’s 110-184 thousand dollars a year saved by students, just because of one open book adopted in a couple of large lecture classes. Presumably, the adoption rate can only go up, so this number will go up, just from one of my books (savings from the real analysis book are going to be much smaller due to less students taking that kind of class).

Now I have nothing against the publishers, but they have their incentives wrong. Boyce-DiPrima is a fine book, but … There is really no reason to print big bulky books on expensive paper for these classes. Locally printed coursepacks or cheaply printed paperbacks are much more efficient. And the students might actually keep their books and they might help them along in other classes. Currently most students return their books as soon as they can to recover most of the cost. So if you’re teaching say a PDE class as I did this semester, you can hardly tell them to brush up on their calculus from their calculus book. They don’t have it anymore!

The incentive for me is to simply make the best book because I want to (makes me feel good, that’s I guess all I can expect). Since I make almost no money on it, I don’t really have to inflate page count just to make it more expensive, or add color and pretty pictures just for the hell of it (it would make the book quite a bit more expensive). Plus the book is more accessible. I already know students use the web version even from their phones.

So anyway, I guess I’m providing at least 2 to almost 4 times my salary in free books.

Anyway, if you do want to buy the books (and I make $2.50 on each, yay! I made almost $400 so far, it’s mostly for making me feel good rather than making money), here are the links to lulu:

Real Analysis, $13.09 + shipping

Differential equations, $16.78 + shipping

Yes, I’m a fan of arbitrary looking prices. Actually the reason for those prices is that I simply set the price so that I get $2.50 from the book, so it’s the (cost of printing)+2.50+(lulu’s cut).