Matlab is the program to use. Any way to help?

Water utility companies would like to avoid freezing water mains, which is why they bury them in the ground. The question is how deep should they be buried? Newton's law of cooling can be used to provide a good estimate. If uniform soil conditions are assumed, then according to this law, the temperature T(x,t) at a depth x below the surface of the ground and time t is given approximately by T(, ) - T 7. T; -T = erf Here T is the temperature at the ground surface, T; is the initial temperature of the soil and a is the thermal conductivity of the soil. Suppose that T; = 5C (the average temperature in Boise in November), T = -5C (the average temperature over the longest period of freezing temperatures in Boise), and a = 0.138 10-6 m2/s (an estimate of the average thermal conductivity properties of soil). (a) Determine how deep a water main should be buried so that it will not freeze until at least 30 days' exposure. Report your value with the correct units. Explain the choice of the method you used to solve the problem The function erf in (2) is called the error function and is available in Matlab using erf. (b) Look up the actual frost line penetration depth for Boise and compare your result. Does the comparison reinforce your trust in your numerical result