1. The problem statement, all variables and given/known data Write an expression that describes the pressure variation as a function of x and t for the waves in air (0∘C) if the air molecules undergo a maximum displacement equal to the diameter of an oxygen molecule, about 3.0×10^−10m. Assume a sound-wave frequency of 55 Hz. Express your answer in terms of the variables x, t, and appropriate constants using two significant figures. 2. Relevant equations ∆P = -∆Pmax cos(kx-wt) ∆Pmax= BAk = rho v^2 A K = 2pi rho v A f (where v is velocity) V sound in air = 331.3 m/s + 0.6t (in celcius) 3. The attempt at a solution Plugging into the formulas I get: v sound in air = 331.3m/s so ∆Pmax = 2 pi (1.29 kg/m^3) 331.3m/s (3 x 10^-10m) 55 Hz = 4.43 x 10^-5 k = 2pif/v = 1.04 w = 2 pi f = 345.57 Final Answer : ∆P = - 4.4 x 10^-5 cos(1.0x - 350t) I also tried with the ∆P =∆Pmax sin (kx - wt) version of the formula, and the website says both are wrong. I'm not really sure where I'm going wrong with this problem; thanks for any help!