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45^(n+4)/(3^(2*n+7)*5^(n+3))

Sum of series 45^(n+4)/(3^(2*n+7)*5^(n+3))



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The solution

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  oo                 
____                 
\   `                
 \          n + 4    
  \       45         
   )  ---------------
  /    2*n + 7  n + 3
 /    3       *5     
/___,                
n = 1                
$$\sum_{n=1}^{\infty} \frac{45^{n + 4}}{3^{2 n + 7} \cdot 5^{n + 3}}$$
Sum(45^(n + 4)/((3^(2*n + 7)*5^(n + 3))), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\frac{45^{n + 4}}{3^{2 n + 7} \cdot 5^{n + 3}}$$
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
$$a_{n} = 3^{- 2 n - 7} \cdot 45^{n + 4} \cdot 5^{- n - 3}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(225^{n + 4} \cdot 3^{- 2 n - 7} \cdot 3^{2 n + 9} \cdot 45^{- n - 5} \cdot 5^{- n - 3}\right)$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
The answer [src]
oo
$$\infty$$
oo
The graph
Sum of series 45^(n+4)/(3^(2*n+7)*5^(n+3))

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