Calc101.com

Automatic Calculus, Matrix Algebra, and Polynomials

George Beck

Wolfram Research, Inc.

Homepage

Welcome all and thank you for coming.

Let's start with the calc101.com homepage.

Calc101.com has been open for business since 1999. Usage and revenue continues to increase increasingly, but unfortunately not increasingly increasingly.

The beauty of delivering -- I mean over-delivering -- software over the web is that you can

1) fix bugs without a recall

2) develop new features incrementally

3) monitor use and get feedback from users so that you know 
	what to document, 
	what to fix, and 
	what to drop.

the basic philosophy

The basic philosophy has two principles and one goal: make the site fast-and-easy and over-deliver to get bigger.

fast-and-easy

minimize text

I minimize text on the pages since no one likes to read long-winded explanations. And with less text, students quickly get to the live pages, which is what I'm selling.

Less text also allows easier translation into foreign languages.

minimize links and clicks

Minimal links and clicks are another way the site is easy-to-use.

On the matrix algebra page http://www.calc101.com/webMathematica/matrix-algebra.jsp a user can see solutions without typing any matrix entries at all: one pull-down and one click is enough. I could have made it a one-click operation, but I didn't want people idly clicking the same button -- they have to do at least a little work.

By the way, in terms of external links calc101.com is a black hole: no links out, only in. Why send anyone away? Think of department stores that are so easy to enter but so hard to escape. You might see something to buy.

Over-deliver

There is a lot of competition on the web in math; most is free, written by teachers, and it is hard to stand out in such a noisy crowd. (Searching google for calculus gives almost 3 million hits; calc101.com is currently #12.)

Over-delivering creates the most important kind of marketing: word-of-mouth promotion.

I try to over-deliver in everything I can think of: features, number of solutions, policies, whatever.

The Pages

the homepage

Coming back to the homepage, you can see on the top right the various things a student can do. I wish there were more but it is hard to write programs that show detailed steps. I have a long list of plans for the future.

Most things on most pages are free. There are only five types of problems that need a password: 

step-by-step integrals, 
solutions of linear equations, 
matrix inverses and determinants, 
and what I call complete graphical analysis.

The stored derivatives and integrals at the bottom right of the home page show sample inputs and sample solutions.

Actually no one really needs to buy a password for the integrals, because there are more than enough stored examples to learn how to do it. But people get stuck, not knowing which method to use or wanting to check their work, and they sometimes like to try variations and to experiment.

the derivatives page

The derivatives page is free for four reasons:

1) It takes a while to get used to inputting functions. Paying customers sometimes gets huffy and upset if they get into trouble. If solutions are free they don't complain as much. So the derivatives page trains the students on input.

2) Also, this page gets them to use the system fast, with no impediments. I don't ask them to register or fill in a questionnaire. I just give, give, give as much as they want.

3) Some educational sites will not link to purely commercial sites. There needs to be enough on the site that is free.

4) The higher the usage, the more the site gets known to students, parents, and teachers, the higher it ranks on search engines, and the more likely it is that other people running other sites will link in.

the integrals page

In the first semester students do derivatives, in the second semester they do integrals. Integrals are a lot harder than derivatives. So I hope that the students who got a benefit from the derivatives page will pay for a password to do integrals. One percent do.

To get a full step-by-step answer on the integrals page you need a password. However, according to the principle of over-delivering, if someone doesn't use a valid password, I should give them something. So I give them the last step for free; that means the answer but no intermediate steps.

Of course, the Integrator at www.integrals.com would also give them the answer for free, and in fact calc101 will fail on many integrals that the Integrator solves. But the student does not necessarily know about the Integrator; it isn't advertised. When people email me about a particular integral calc101 cannot handle, I tell them about the Integrator.

the matrix algebra page

I like the matrix algebra page because it gives so much. It gave me the chance to massively over-deliver.

As usual they get all the answers without a password, and most of the operations are shown step-by-step for free, too. Passwords give them the steps for the more complicated problems.

Although this page has not generated as much direct traffic or income as the calculus pages, it has allowed me to advertise using a different set of google adwords. People who would not have seen the calculus pages in some other way learn about them because of the matrix algebra page.

the graphing page

The graphing page allows new approach that I am planning to use to attack the high school market: rather than show steps I give a complete analysis.

Users get the graph of their function without a password, but with the password they get much more: with one input and one click they get over 80 graphs. Over-deliver! I love it.

the polynomial pages

Not much to say about the polynomial multiplication and division pages except that they draw some traffic.

Foreign Languages

Before the matrix algebra and graphing pages existed, I had the site translated into Spanish, German, French, and Japanese.

Although Spanish gave more impressions and more click-throughs from google ads than English, people weren't paying anywhere near as often as for the English pages. German and French had lower volume, but they weren't paying often enough, either. So I stopped advertising and haven't translated any of the new material for those languages. Cut your losses.

The Japanese site faltered in a different way. Only in M- 5.0 do Japanese characters show up in Linux. I've been working on a major update of the site, and that is one of the more important fixes. I will start advertising in Japan after the update.

Chinese? Sure, later.

Passwords

This is where the money comes from.

As I add new pages I will continue to let people with old passwords enjoy the new features; yet again, over-deliver.

Back in 1998 I had thought of charging $1 per solution. Now I give 50 to 100% more solutions than advertised, and on average a solution costs less than one cent. Very few people have ever used 10% of what they get.

Advertising

I maximize advertising, spending over 60% of income on online ads, mainly google. Driving volume up creates a snowball effect. Over the last year the site has averaged more than 6000 page requests per day; over the last month 24,000 per day. For comparison, MathWorld gets around 280,000 and the Integrator around 13,000 per day.

I wrote a flurry of email to other math sites for a summer of Saturday mornings, but I don't go to shows, write press releases, or do any other kinds of marketing. This is the second talk I've given on the site, for example. To me, the most important thing to spend time on is developing new features.

Conclusion

Finally, let me say that my goal is to gain 1% control of the whole calculus market. I estimate calc101 is around 1/5% now, so there is a ways to go.

Thank you for your kind attention.