Lesson Worksheet: Sum of a Finite Geometric Sequence Mathematics • 10th Grade
In this worksheet, we will practice calculating calculate the sum of the terms in a geometric sequence with a finite number of terms.
Q1:
We can find a formula for the sum of a geometric series. Consider the series
Multiply the expression for by , the common ratio.
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So, we have and
The right-hand sides of the equations are very similar. Identify the terms that do not appear on the right-hand side of both equations.
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Now, consider the subtraction
Use the answer to the previous part to simplify the subtraction .
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Factor both sides of the equation.
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Rearrange the equation to make the subject of the formula.
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