Rewrite the Series Using Summation Notation $$- \frac { 1 } { 3 } + \frac { 1 } { 6 } - \frac { 1 } { 9 } + \ldots - \frac { 1 } { 21 }$$

question 166

Multiple Choice

Rewrite the series using summation notation. Use 1 as the lower limit of summation.
- $$- \frac { 1 } { 3 } + \frac { 1 } { 6 } - \frac { 1 } { 9 } + \ldots - \frac { 1 } { 21 }$$

• A) \(\sum _ { \mathrm { i } = 1 } ^ { 7 } \frac { ( - 1 ) ^ { \mathrm { i } } } { 3 \mathrm { i } }\)
• B) \(\sum _ { i = 1 } ^ { 7 } \frac { ( - 1 ) ^ { i } } { 3 ^ { i } }\)
• C) \(\sum _ { i = 1 } ^ { 7 } \frac { ( - 1 ) ^ { i - 1 } } { 3 i }\)
• D) \(\sum _ { i = 1 } ^ { 7 } \frac { ( - 1 ) ^ { i - 1 } } { 3 ^ { i } }\)

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