I had thought the eqn of simple harmonic motion is a sinusoidal function of time, with the eqn being:(adsbygoogle = window.adsbygoogle || []).push({});

x(t) = A sin(wt + ∅0)

Halfway down this page:

http://electron9.phys.utk.edu/phys135d/modules/m9/oscillations.htm [Broken]

in Problems:

in solution (a) it gives;

The displacement as a function of time is x(t) = Acos(ωt + φ).

Why are they using a cos and not a sin function?

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# Eqn for SHM, sin function, so why cos?

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