Center of mass rigid body, the gravity forces will not cause the body to rotate, which means the weight of the body can be considered to be concentrated at the center of mass. The linear and angular momentum of a collection of particles can be simplified by measuring the position and velocity of the particles relative to the center of mass. Let the system of particles "P", "i"=1...,"n" of masses "m" be located at the coordinates r with velocities v. Select a reference point R and compute the relative position and velocity vectors, The total linear and angular momentum vectors relative to the
Proof of the Euler product formula for the Riemann zeta function arithmetic, the partial product when expanded out gives a sum consisting of those terms "n" where "n" is a product of primes less than or equal to "q". The inequality results from the fact that therefore only integers larger than "q" can fail to appear in this expanded out partial product. Since the difference between the partial product and ζ("s") goes to zero when σ > 1, we have convergence in this region. Proof of the Euler product formula for the Riemann zeta function Leonhard Euler proved the Euler product formula for the Riemann zeta function in his thesis "Variae