Radius of Convergence
radius of convergence
[′rād·ē·əs əv kən′vər·jəns]Radius of Convergence
The radius of convergence of a power series is the radius of the circle of convergence. In other words, it is the number r such that the power series
converges when ǀzǀ > r and diverges when ǀzǀ > r.