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.

Answer 1

You must use S=a/1-r
so you plug the number in S=.79/1-.1
which is S=.79/.9 so we have 79/90 as our answer
btw S=sum a= first number in sequence r=common ratio
hope this makes sense