###### Alissa Fong

MA, Stanford University
Teaching in the San Francisco Bay Area

Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts

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# Geometric Series - Problem 14

Alissa Fong
###### Alissa Fong

MA, Stanford University
Teaching in the San Francisco Bay Area

Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts

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A geometric sequence is a number pattern where you multiply a term by some fixed ratio, r, in order to get the next term. We can find any term in the list using a shortcut formula called the explicit formula. We could also describe the pattern using a recursive formula, but it's less useful because we'd need to know the term before in order to find a new term. If you want to add these terms in your pattern, then you have what is called a geometric series. It is often represented using capital Greek letter Sigma. To find a sum, you'll need to know how many terms you're adding, the first term, and the ratio, r, for the pattern.

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