# June, 2013

## Secrets of the Mathematical Ninja: Taylor series and the product rule

$f(x)$, it turned out, was $x^2 \tan(x)$. "That's going to be a pain to differentiate," said the student, sighing. Taylor series were not his favourite; differentiating trig functions just made matters worse. "I have a trick," said the Mathematical Ninja. "Will it save me a lot of work?" "It will."

## Silly Questions Amnesty

Want a silly answer? You know what to do.

## The butterfly isn’t to blame

When I was about 12, and my brother about 10, one of us1 threw a lump of coal at the other. The coal ricocheted around our living room and smashed an ornament. In the subsequent inquest, both of us tried to blame the other, as brothers do; he reasoned, perversely,

## The Mathematical Ninja’s Guide To Famous Triangles

"$\arccos\left(\frac{1}{3}\right)$", said the student, absent-mindedly. The Mathematical Ninja, without thinking, said "$1.23$." "It says $70.5$ here… but, but," said the student, realising that the Mathematical Ninja was not going to accept answer like that, "my calculator has… somehow… got switched into degree mode, haha, let me fix it. Ah, yes,