A history graph at x = 1.5 m of a wave traveling in the negative x-direction at 3.2 m/s. [Answer in 3 significant figures] D (cm) 2 1.27 cm -1 -2 0,2 04 06 0.8 12 t(S) a) (5 pts) What is the wavelength of the wave? b) (14 pts) Using sine function to describe the wave, what is the initial phase constant of the wave if D(x = 1.5, t = 0) = 1.27 cm? c) (6 pts) Write a complete expression (in terms of sine function) for the displacement of the string as a function of position x and t in SI units.