What is a partial sum of an infinite series? Calculus Tests of Convergence / Divergence Infinite Series 1 Answer Wataru Aug 30, 2014 A partial sum Sn of an infinite series ∞∑i=1ai is the sum of the first n terms, that is, Sn=a1+a2+a3+⋯+an=n∑i=1ai. Answer link Related questions How can an infinite series have a finite sum? How do you evaluate an infinite series? How do you find the sum of an infinite series? How does an infinite geometric series apply to being pushed on a swing? What are infinite series used for? What is a convergent infinite series? What is a divergent infinite series? What is an oscillating infinite series? What is a telescoping infinite series? What is a collapsing infinite series? See all questions in Infinite Series Impact of this question 2739 views around the world You can reuse this answer Creative Commons License