In high school, if not sooner, one learns theorems established more than two millenia ago by Euclid and Archimedes. I am thinking of the theorems expressed today by the equations
𝐶 = 2π𝑟,
𝐴 = π𝑟²
for the circumference and area of a circle whose radius is 𝑟, and
𝐴 = 4π𝑟²,
𝑉 = (4/3)π𝑟³
for the surface area and volume of a sphere whose radius is 𝑟. Continue reading
Polytropy 