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Find the sum of the first 30 terms of the sequence below an=3n+2
4 months ago
Q:
find the sum of the first 30 terms of the sequence below an=3n+2
Accepted Solution
A:
first off, let's find the 1st term's value, and the 30th term's value,
[tex]\bf a1=3(1)+2\implies a1=5\qquad \qquad \quad a30=3(30)+2\implies a30=92\\\\ -------------------------------\\\\ ~~~~~~~\textit{ Sum of an arithmetic sequence}\\\\ S_n=\cfrac{n(a1+an)}{2}~ \begin{cases} n=n^{th}\ term\\ a1=\textit{first term's value}\\ ----------\\ a1=5\\ a30=92\\ n=30 \end{cases} \implies S_{30}=\cfrac{30(5+92)}{2} \\\\\\ S_{30}=15(97)[/tex]