Series and Sum Calculator with Steps

Calculate series and sums step by step

This calculator will try to find the infinite sum of arithmetic, geometric, power, and binomial series, as well as the partial sum, with steps shown (if possible). It will also check whether the series converges.

Leave empty for autodetection.
If you need a binomial coefficient $$$C(n,k) = {\binom{n}{k}}$$$, type binomial(n,k).
If you need a factorial $$$n!$$$, type factorial(n).

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Your Input

Find $$$\sum_{n=1}^{\infty} 3^{- n}$$$.

Solution

$$$\sum_{n=1}^{\infty} 3^{- n}$$$ is an infinite geometric series with the first term $$$b=\frac{1}{3}$$$ and the common ratio $$$q=\frac{1}{3}$$$.

By the ratio test, it is convergent.

Its sum is $$$S=\frac{b}{1-q}=\frac{1}{2}$$$.

Therefore,

$${\color{red}{\left(\sum_{n=1}^{\infty} 3^{- n}\right)}}={\color{red}{\left(\frac{1}{2}\right)}}$$

Hence,

$$\sum_{n=1}^{\infty} 3^{- n}=\frac{1}{2}$$

Answer

$$$\sum_{n=1}^{\infty} 3^{- n} = \frac{1}{2} = 0.5$$$A