Calculus 2 | 20.4: Radius and Interval of Convergence

Full course — free exercises, Feynman reviews, and AI-graded feedback: https://ludium.ai/courses/calculus-2 A power series is secretly a function, but it only lives on part of the number line. This video finds that home: an interval centered at c and governed by a single number called the radius of convergence. Key concepts covered: The domain of a power series is always an interval centered at c The three possibilities: radius zero, radius infinity, or a finite radius R Turning the absolute value inequality into the open interval Why the endpoints must always be checked separately Using the ratio test to find the radius, with the factorial and even-power extremes ━━━━━━━━━━━━━━━━━━━━━━━━ SOURCE MATERIALS The source materials for this video are from    • Calculus 2 Lecture 9.7:  Power Series, Cal...