Where C is the concentration in mg/L and x is the position in km downstream from a water treatment plant. Use the false position and secant method with Excel (calculate your answers to 1% error) to get an approximation of the distance downstream where: To. The concentration will be below 5 mg/L. b. The concentration will start to be above 5 mg/L again. Also during your resolution: . Propose assumptions / initial values in order to start the calculations with the graph below. ii. Compare the convergence of the two methods. If a method diverges, explain why. iii. What is the total distance over which the concentration is below 5 mg/L in the river? Concentration (mg/L) 12 10 8 50 2 0 0 2 6 Distance (km) 4 5 mg/L 8 10