- #1
mr.tea
- 102
- 12
Homework Statement
The problem states: In the harmonic series ##\sum_{1}^{\infty} \frac{1}{k}##, all terms for which the integer ##k## contains the digit 9 are deleted. Show that the resulting series is convergent.
Hint: Show that the number of terms ##\frac{1}{k}## for which ##k## contains no nines and ##10^{p-1} \leq k < 10^p## is less than ##9^p##.
Homework Equations
The Attempt at a Solution
Well, it is not hard to show and see the required in the hint, but other than that the sum of less terms will be smaller than the original number of terms in the harmonic series, I am not sure how I can deduce the convergence. Can't see any link to convergence.
I would be happy to get help in this exercise.
Thank you.