Surface of revolution never negative, the area is given by If the curve is described by the function , , then the integral becomes for revolution around the -axis, and for revolution around the "y"-axis (using ). These come from the above formula. For example, the spherical surface with unit radius is generated by the curve , , when ranges over . Its area is therefore For the case of the spherical curve with radius , rotated about the -axis A minimal surface of revolution is the surface of revolution of the curve between two given points which minimizes surface area. A basic
Einstein solid Walther Nernst learned of Einstein's 1906 paper on specific heat, he was so excited that he traveled all the way from Berlin to Zürich to meet with him. The heat capacity of an object at constant volume "V" is defined through the internal energy "U" as formula_3, the temperature of the system, can be found from the entropy To find the entropy consider a solid made of formula_5 atoms, each of which has 3 degrees of freedom. So there are formula_6 quantum harmonic oscillators (hereafter SHOs for "Simple Harmonic Oscillators"). Possible energies of an SHO are given by or, in