Cesaro summability implies bounded partial sums

[stripes]

Homework Statement

Suppose c_{n} > 0 for each n\geq 0. Prove that if \sum ^{\infty}_{n=0} c_{n} is Cesaro summable, then the partial sums S_{N} are bounded.

Homework Equations

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The Attempt at a Solution

I tried contraposition; that was getting me nowhere. I have a few inequalities here and there but they don't tell me anything. I need to show that there exists an upperbound for the partial sums. This means there exists a least upperbound. I need to find that least upperbound. Becausec_{n} > 0 for each n\geq 0, then the series is nondecreasing, which means the partial sums are nondecreasing, so we are looking for an upperbound, not a lowerbound.

 

[pasmith]

Homework Statement

Suppose c_{n} > 0 for each n\geq 0. Prove that if \sum ^{\infty}_{n=0} c_{n} is Cesaro summable, then the partial sums S_{N} are bounded.

Homework Equations

--

The Attempt at a Solution

I tried contraposition; that was getting me nowhere. I have a few inequalities here and there but they don't tell me anything. I need to show that there exists an upperbound for the partial sums. This means there exists a least upperbound. I need to find that least upperbound.

That least upper bound, if it exists, is \lim_{n \to \infty} S_n, which is the definition of \sum_{n=0}^{\infty} c_n in the traditional sense.