Mastodawn

was helping my kid with trig, he had a problem like sec(pi/4*x -pi/2) and it wanted the period and the phase shift.

now words aren't always uniformly defined even in math, but to my mind this thing has period 8, and phase shift pi/2 but he wanted to say phase shift was 2 based on rewriting the argument as pi/4*(x-2)

which would you expect to be the definition of phase shift in a precalculus text?

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Stephanie 🎀

@dlakelan I’m thinking pi/2 is the phase shift. If you’re going to merge the denominators like that, the numerator should look different. 2pi/8x - pi*4x/8x = 2pi(1 - 2x)/8x = pi(1 - 2x)/4x. That muddies things up anyway- the phase shift is sitting right there and I see no reason to rewrite the argument.