c) For a typical soil, K = 0.3 x 10-6 m2/s. Over a period of one year, calculate D and hence find the peak-peak variation of temperature at depths of 1-10 m for the cases To=15C, a(0) = 20C. (This part is easy and difficult at the same time. You need to use T(z,t) equation to obtain the values of T at different depths. When using MS Excel, convert Sin and Cos (if needed) into radians. Convert 1 year into seconds which will be your t, and the period w=21t/t. Please take care of units throughout.) The author of this problem has mentioned the solution at z=1, 3, and 5 m as T = 22C, 6.8C, and 2.1C, respectively. However, I obtained answers as T= 16.1C, 15.3C, and 15.1C. At the moment, I believe my answers are correct but I am open to see if I am doing something wrong here. I will check this solution very carefully