## Archive for October 31, 2011

### Trig or Treat

On Mischief Night, I spent a long time explaining our Halloween decorations to my neighbor. But I understood why he was confused. After all, they didn’t *look* like Halloween decorations.

There was the WITCH of Agnesi taped to our front door…

…the SKELETON of a cube hanging from our tree…

…and Napier’s BONES drawn on the sidewalk in chalk.

After I set our neighbor straight, I went for a walk in the woods.

I came across a mathematician stirring a cauldron in the middle of an open clearing. One by one, she added the eye of a newt, two whiskers from a black cat, a pinch of wolf’s bane, a dash of bat’s blood, three hairs from a mermaid, the ear of a troll, and finally a dollup of dragon’s breath. I asked her, “Why don’t you just add everything at the same time?”

“Oh, no,” she said. “To make an effective potion, the ingredients must be integrated by parts.”

Finally, a math equation for today: