Prove that the area of an irregular parcel land enclosed by curvilinear figure can be used to compute the are of a plot of computed using the formula below .Area=×\3(×_2Q+4E).the working using Simpson rule in survey

Asteam is contained in a rigid tank with a volume of 1 m3. initially, the pressure and temperature are 7 bar and 500 oc, respectively. the temperature drops due to cooling process. determine: (1) the temperature at which condensation begins in °c, (2) the fraction of the total mass that has condensed when the pressure decreased to 0.5 bar. (3) the volume in m3 occupied by saturated liquid at the final state?