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Arithmetic sequences and series — Homework
Identify a_1 and d before reaching for either formula.
- 1.Find the 12th term of the arithmetic sequence with a_1=9, d=5.
- 2.Find a_15 and the sum of the first 15 terms of the sequence 6, 10, 14, 18, ...
- 3.An arithmetic sequence has a_1=80 and d=-7. Find a_9.
- 4.A theater has 18 rows. Row 1 has 20 seats, and each row after has 3 more seats than the one before. How many seats in row 18, and how many in total?
- 5.Using the Gauss pairing idea, explain why S_n = (n/2)(a_1+a_n) works even when n is odd (leaving one term unpaired).
🌲 Homeschool of the FutureEleventh Grade · Math · week 30 homework