18 flashcards · Shared on 19 August 2026 by AtomAI Library
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What distinguishes a series from a sequence?
A series is the sum of the terms of a sequence
What distinguishes a series from a sequence?
A series is the sum of the terms of a sequence
Which property defines an arithmetic sequence?
The difference between consecutive terms is constant
Which property defines a geometric sequence?
The ratio of each term to the preceding nonzero term is constant
If an arithmetic sequence has first term a and common difference d, which formula gives its nth term?
a + (n - 1)d
If a geometric sequence has first term a and common ratio r, which formula gives its nth term?
ar^(n - 1)
What is the common difference of the arithmetic sequence 14, 9, 4, -1, ...?
-5
What is the common ratio of the geometric sequence 48, -24, 12, -6, ...?
-1/2
What is the 20th term of the arithmetic sequence 5, 9, 13, 17, ...?
81
What is the 8th term of the geometric sequence 3, 6, 12, 24, ...?
384
Which formula gives the sum S_n of the first n terms of an arithmetic sequence with first term a and common difference d?
S_n = n/2[2a + (n - 1)d]
An arithmetic sequence has first term a and nth term l. Which expression gives the sum of its first n terms?
n/2(a + l)
What is the sum of the first 20 terms of the arithmetic sequence 5, 9, 13, 17, ...?
860
For r ≠ 1, which formula gives the sum of the first n terms of a geometric sequence with first term a and common ratio r?
a(1 - r^n)/(1 - r)
What is the sum of the first six terms of the geometric sequence 2, 6, 18, 54, ...?
728
When does an infinite geometric series with first term a and common ratio r have a finite sum?
When |r| < 1
What is the sum to infinity of the geometric series 12 - 6 + 3 - 1.5 + ...?
8
Three numbers form an arithmetic sequence. The first is 7 and the third is 19. What is the middle number?
13
For positive numbers x and y, which expression is their geometric mean?
√(xy)