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“A lot of the basic trig ‘identities’ are nothing more than Pythagoras’ theorem,” explains Anderson, referring to equations that describe relationships among different trigonometric functions.

“Pythagoras’ theorem tells us,” Hughes writes, that |Vx|2 + |Vy|2 + |Vz|2 = V2.

And of course there are some longstanding but incorrect traditions, such as “Pythagoras’ theorem” and “St James’ Park”, the official name of Newcastle United’s stadium.

“There was always this warm-up period where kids were talking about movies or television, and then there’d be this abrupt transition to Pythagoras Theorem,” he says.

You could have s and s that are prime numbers, s and s that are square roots of successive integers or s and s that represent the Pythagoras theorem for a unit rectangle.