nathanboff
nathanboff nathanboff
  • 04-07-2019
  • Mathematics
contestada

What is the sum of the geometric series?
4
E (-2)(-3)^n-1
n=1

A. –122
B. –2
C. 40
D. 54

Respuesta :

r3t40
r3t40 r3t40
  • 04-07-2019

[tex]

\Sigma_{n=1}^{4}-2\cdot(-3)^{n-1} \\

(-2)(-3)^{1-1}+(-2)(-3)^{2-1}+(-2)(-3)^{3-1}+(-2)(-3)^{4-1} \\

-2+6-18+54 \\

\boxed{40}

[/tex]

So the answer is C,

[tex]\Sigma_{n=1}^{4}-2\cdot(-3)^{n-1}=40[/tex]

Hope this helps.

r3t40

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