Problem 155 of 7
Determine whether the geometric-series formula applies when the common ratio is 1/3.
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handle constant series separately.
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Handle the r=1 exception separately.
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Solution
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1. Check whether the denominator 1-r would be zero.
2. If r=1, use repeated addition.
3. If r!=1, use the finite geometric formula and interpret signs if needed.
Use the worked steps, then substitute the final answer back into the original relationship to confirm it satisfies the prompt.
Division by zero in the finite-series formula.