Matbog.dk

All right, all right. It's here, yay! Tomorrow is "Epic π-day".

My lack of enthusiasm is due to several errors in the meme going around:

1) Since π is irrational, it is not "equal to" any number with finitely many digits. The "=" should be a "≈".

2) The rounding is wrong. Since the next digit is a "5", one should round up, not down. So, 9:26:54, or even better: Somewhere in between those two, slightly closer to 9:26:54.

3) It only works if you write dates in the (highly non-standard) way that americans do. Month-day-year is so illogical it should be illegal. The ISO standard is YYYY-MM-DD. And it has the huge advantage that sorting dates alphabetically also sorts them chronologically.

But then again, we wouldn't have a pi-day if everyone followed the ISO standard.

Happy Pi-day, everyone! Please point out the above errors to anyone posting the meme, and raise mathematical awareness!

Just one day to go!

Yup.

And that point, right in the middle, where the Pringle appears to be perfectly horizontal is called a "saddle point" for a very good reason. :)

The "c" in the equation is actually almost redundant. The only effect is has is that when it's negative, it turns the Pringle upside-down. Everything else it does can also be achieved by changing the value of a and b.

Have a lovely day!

(This is yet another post in English. There is a Danish translation in the first comment below.)

*Discusssion time*

This page is suddenly getting quite a lot of international visitors, thanks to Facebook-god, blessing us with a "like". Most of you are probably just passing by, deciding that a page for a danish math book is just a bit too weird. But others come back, and some of you have even "liked" us.

So my question is: Should this page aim to evolve into an international forum for intermediate-level (age group 15-20) math?

The original book, (matbog.dk) is, and will always be, a guide to the *danish* approach to learning math. It would not make sense to translate that into other languages.

But I don't see anything wrong with this page becoming a place where you can meet strangers from other countries with other curriculums, and be pleasantly surprised about how much math you still have in common.

I can keep posting danish translations of every post in the first comment.