Problem

Algebra \( 2> \) CC. 19 Partial sums of geometric series 9JU
Find the \( 12^{\text {th }} \) partial sum of the geometric sequence \( a_{n}=3 \cdot 2^{n-1} \).

Answer

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Answer

\( S_{12} = 3(1 - 2^{12}) \)

Steps

Step 1 :\( S_{12} = \frac{a_1(1 - r^{12})}{1 - r} \)

Step 2 :\( S_{12} = \frac{3(1 - 2^{12})}{1 - 2} \)

Step 3 :\( S_{12} = 3(1 - 2^{12}) \)

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