2. A water stream containing 0.5mg/L of DCX enters a 4ft long bed of activated carbon. The concentration of DCX as it flows through the bed is described by this partial differential equation: (1+B1Bk1)tc+uzcEz22c=0 Here, time is in seconds and z is in feet, B is the bed void fraction, u is the fluid velocity in feet/s, and E is the dispersion coefficient in sft2. (a) Using a step size of 0.5 feet and these approximations tctci,j+1ci,jzc21[zci+1,j+1ci,j+1+zci,j+1ci1,j+1]ifz