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Find the partial sum S7 for the geometric sequence with a=3,r=2.S7=

Find The Partial Sum S7 For The Geometric Sequence With A3r2S7 class=

Sagot :

The formula for the partial sum of a geometric sequence is given by:

[tex]S_n=\frac{a(r^n-1)}{r-1}[/tex]

From the problem, we identify:

[tex]\begin{gathered} n=7 \\ a=3 \\ r=2 \end{gathered}[/tex]

Finally, using these values in the formula:

[tex]\begin{gathered} S_7=\frac{3(2^7-1)}{2-1}=\frac{3(128-1)}{1}=3\cdot127 \\ \\ \therefore S_7=381 \end{gathered}[/tex]