An atom in a molecule oscillates about its equilibrium position with a frequency of 2.00 × 1014 Hz and a maximum displacement of 3.50 nm.

(a) Write an expression giving x as a function of time for this atom, assuming that x = A at t = 0.

(b) If, instead, we assume that x = 0 at t = 0, would your expression for position versus time use a sine function or a cosine function? Explain.