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 #S_n# of an infinite series #sum_{i=1}^{infty}a_i# is the sum of the first n terms, that is, #S_n=a_1+a_2+a_3+cdots+a_n=sum_{i=1}^na_i#. 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 2408 views around the world You can reuse this answer Creative Commons License