Bizarre.<p>The constant <i>e</i> isn't arbitrary, the use of radians (and hence <i>pi</i>) isn't arbitrary, and it certainly doesn't make sense to use degrees and write 180 as 1+1+1+...+1+1.<p>That's just perverse.<p>Observing that -1 is 1 rotated by 180 degrees is simplistic and already begging the question, and then observing that <i>cosh(ix)=cos(x)</i> based on the power series is using huge amounts of machinery that again, begs the question.<p>I can't tell if it's misguided, deliberately provocative, or what. It certainly has the feel of someone being self-consciously clever.