Evaluate the infinite geometric series $0.79 + 0.079 + 0.0079 + 0.00079 + 0.000079 + \dotsb$. Express your answer as a fraction with integer numerator and denominator.

Respuesta :

Given geomatric series 0.79 + 0.079 + 0.0079 + 0.00079 + 0.000079 +.....

First term of the given geomatric series = 0.79.

Common ratio = [tex]\frac{0.079 }{0.79}[/tex] = [tex]\frac{1}{10}[/tex]

Sum of infinite geometric series is given by formula

S∞ = [tex]\frac{a}{1-r}[/tex]

Where, a is the first term and r is the common ratio.

Plgging valus of a and r in above formula, we get

S∞ = [tex]\frac{0.79}{1-\frac{1}{10} }[/tex]

  =[tex]\frac{0.79}{\frac{10-1}{10} }[/tex]

   =[tex]\frac{0.79}{\frac{9}{10}}[/tex]

   = [tex]0.79\times\frac{10}{9}=\frac{79}{10} \times\frac{10}{9} = \frac{79}{9}[/tex]

Therefore,

Sum of the infinite geometric series = [tex]\frac{79}{9}[/tex]

Answer:

79/90

Step-by-step explanation: