Solve with Excel, please.

1. Consider a flat concrete wall of thickness 2L, which is initially at a temperature of 70C, is suddenly immersed in a fluid that is at a temperature of 25C. a) Plot the temperature distributions from a time immediately after after submerging the flat wall until reaching the steady state. Use the following equation seen in class, take the first 20 values of the infinite series (n=20): 00 2 T-T.. 2(-1)" -exp = [-(n+3)*x*e]cos (n+) nux [- n TX* Ti-T n0 =(n+1). b)) Plot the ratio of the total energy transferred from the wall vs the different times) proposed in subparagraph a). Use the following equation: in 5100 Q lo sin 51 Recommendation: Carry out the calculations in an excel sheet