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Revision difference : sum of series
Version 7 Version 6
If a series $\sum_{n = 1}^\infty a_n$ of real or complex numbers is convergent and the limit of its partial sums is $S$, then $S$ is the {\em sum of the series}. \,This circumstance may be denoted by If a series $\sum_{n = 1}^\infty a_n$ of real or complex numbers is convergent and the limit of its partial sums is $S$, then $S$ is the {\em sum of the series}. \,This circumstance may be denoted by
$$\sum_{n = 1}^\infty a_n = S$$ $$\sum_{n = 1}^\infty a_n = S$$
or equivalently or equivalently
$$a_1+a_2+a_3+... = S.$$ $$a_1+a_2+a_3+... = S.$$
Nevertheless, one should not think that this means an addition of infinitely many numbers --- it's only a question of the limit Nevertheless, one should not think that this means an addition of infinitely many numbers --- it's only a question of the limit
$$\lim_{n\to\infty}\underbrace{(a_1+a_2+...+a_n)}_{\textrm{partial sum}}.$$ $$\lim_{n\to\infty}\underbrace{(a_1+a_2+...+a_n)}_{\textrm{partial sum}}.$$
The sum of the series is equal to the sum of a partial sum and the corresponding remainder term. The sum of the series is equal to the sum of a partial sum and the corresponding remainder term.