Question

Find the sum of the geometric series with the following values a1=1; r=4; n=5

Answer 1

dati:

a1=1

r=4

n=5

s5=¿?

solving:

formulati:

$s_{n}=a_{1}.\frac{r^{n}-1}{r-1} \\ \\ \\s_{5}=1.\frac{4^{5}-1}{4-1}\\ \\ \\s_{5}=1.\frac{1024-1}{3}\\ \\ \\s_{5}=1.\frac{1023}{3}\\ \\ \\s_{5}=341$

sum of the n = 5 terms is:

341

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