- #1
agnimusayoti
- 240
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- Homework Statement
- ML Boas gave an example to find ##S_n##; ##S##, and ##R_n## of a series that follow this rule:
$$\sum^{\infty}_{2} \frac {2}{n^2-1}$$.
He show that I have to change the formula of the rule before determine ##S_n##; ##S##, and ##R_n##
- Relevant Equations
- I can catch up the following explanation. But I still don't understand why he choose to change the form rather than use the initial formula.
1. Is it because the initial formula start the series from ##n = 2##?
2. If the initial formula is used, can I find ##S##, which $$S=\lim_{n\to\infty} \frac{2}{n^2-1}=\frac{2}{\infty}=0$$? Why that answer is different if the formula is changed.
2. If the initial formula is used, can I find ##S##, which $$S=\lim_{n\to\infty} \frac{2}{n^2-1}=\frac{2}{\infty}=0$$? Why that answer is different if the formula is changed.