Mister Exam

Other calculators


ln(n+2)/n*1/(3n+7)^1/2

Sum of series ln(n+2)/n*1/(3n+7)^1/2



=

The solution

You have entered [src]
  oo               
_____              
\    `             
 \     /log(n + 2)\
  \    |----------|
   \   \    n     /
   /   ------------
  /      _________ 
 /     \/ 3*n + 7  
/____,             
n = 1              
$$\sum_{n=1}^{\infty} \frac{\frac{1}{n} \log{\left(n + 2 \right)}}{\sqrt{3 n + 7}}$$
Sum((log(n + 2)/n)/sqrt(3*n + 7), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\frac{\frac{1}{n} \log{\left(n + 2 \right)}}{\sqrt{3 n + 7}}$$
It is a series of species
$$a_{n} \left(c x - x_{0}\right)^{d n}$$
- power series.
The radius of convergence of a power series can be calculated by the formula:
$$R^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}$$
In this case
$$a_{n} = \frac{\log{\left(n + 2 \right)}}{n \sqrt{3 n + 7}}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\frac{\left(n + 1\right) \sqrt{3 n + 10} \log{\left(n + 2 \right)}}{n \sqrt{3 n + 7} \log{\left(n + 3 \right)}}\right)$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
The answer [src]
  oo               
____               
\   `              
 \      log(2 + n) 
  \   -------------
  /       _________
 /    n*\/ 7 + 3*n 
/___,              
n = 1              
$$\sum_{n=1}^{\infty} \frac{\log{\left(n + 2 \right)}}{n \sqrt{3 n + 7}}$$
Sum(log(2 + n)/(n*sqrt(7 + 3*n)), (n, 1, oo))
Numerical answer [src]
2.66039456310106764014285696179
2.66039456310106764014285696179
The graph
Sum of series ln(n+2)/n*1/(3n+7)^1/2

    Examples of finding the sum of a series