contestada

Write an expression that gives the requested sum.
The sum of the first 20 terms of the geometric sequence with first term 6 and common ratio 3
s20 =

Respuesta :

Answer:

The expression to give the requested sum after simplifying, [tex]S_{20}[/tex] = [tex]{3(3^{20}-1) }[/tex]

Step-by-step explanation:

To find the sum of first 20 terms,

a = 6, r = 3

By formula, [tex]S_{n} = \frac{a(r^{n}-1) }{r-1}[/tex]

substitute the values in the above formula, the equation becomes,

[tex]S_{20} = \frac{6(3^{20}-1) }{3-1}[/tex]

[tex]S_{20} = \frac{6(3^{20}-1) }{2}[/tex]

[tex]S_{20}[/tex] = [tex]{3(3^{20}-1) }[/tex]

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