Mister Exam

Other calculators

Sum of series log5(n-i)



=

The solution

You have entered [src]
  oo            
 ___            
 \  `           
  \   log(n - i)
   )  ----------
  /     log(5)  
 /__,           
i = 0           
$$\sum_{i=0}^{\infty} \frac{\log{\left(- i + n \right)}}{\log{\left(5 \right)}}$$
Sum(log(n - i)/log(5), (i, 0, oo))
The radius of convergence of the power series
Given number:
$$\frac{\log{\left(- i + n \right)}}{\log{\left(5 \right)}}$$
It is a series of species
$$a_{i} \left(c x - x_{0}\right)^{d i}$$
- power series.
The radius of convergence of a power series can be calculated by the formula:
$$R^{d} = \frac{x_{0} + \lim_{i \to \infty} \left|{\frac{a_{i}}{a_{i + 1}}}\right|}{c}$$
In this case
$$a_{i} = \frac{\log{\left(- i + n \right)}}{\log{\left(5 \right)}}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{i \to \infty} \left|{\frac{\log{\left(- (i - n) \right)}}{\log{\left(- (i - n + 1) \right)}}}\right|$$
Let's take the limit
we find
True

False

    Examples of finding the sum of a series