FrostGD
contestada

Determine whether the infinite geometric series converges or diverges. If it converges, find the sum, and if it diverges then explain why.

48 + 36 + 27 + 81/4 + ...​

Respuesta :

Geometric series means

  • |r|<1

Lets spot out common ratio

  • 36/48=3/4
  • 27/36=3/4

Its less than 1

Hence series converges

Sum:-

  • a/1-r
  • 48/(1-3/4)
  • 48/1/4
  • 192

Answer:

Series converges

Sum = 192

Step-by-step explanation:

General form of geometric series:   [tex]a_n=ar^{n-1}[/tex]

where:

  • a is the initial term
  • r is the common ratio

Given series:  48, 36, 27, 81/4, ...

[tex]\implies a = 48[/tex]

[tex]\implies r=\dfrac{a_2}{a_1}=\dfrac{36}{48}=\dfrac34[/tex]

Geometric series converges when |r| < 1

Geometric series diverges when |r| ≥ 1

[tex]\textsf{As }r=\dfrac34\ \implies|\dfrac34| < 1\:\implies\:\textsf{series converges}[/tex]

Sum of an infinite geometric series:

[tex]S_\infty=\dfrac{a}{1-r}\quad\textsf{for}\:|r| < 1[/tex]

Substituting values of a and r:

[tex]\implies S_\infty=\dfrac{48}{1-\frac34}=192[/tex]