Sequences & Series Flashcards
7 cards from real TMUA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Sequences & Series flashcards as text
The first term of an arithmetic sequence is 3 and the common difference is 5. What is the 10th term?
Answer: 48
The nth term of an arithmetic sequence is a + (n-1)d = 3 + 9×5 = 48.
In a geometric sequence, the first term is 2 and the common ratio is 3. What is the 5th term?
Answer: 162
The nth term of a geometric sequence is ar^(n-1) = 2 × 3^4 = 2 × 81 = 162.
What is the sum of the first 20 terms of an arithmetic series with first term 4 and common difference 3?
Answer: 650
S_n = n/2 × (2a + (n-1)d) = 20/2 × (8 + 57) = 10 × 65 = 650.
Which of the following sequences is arithmetic?
Answer: 5, 8, 11, 14, ...
5, 8, 11, 14 has a constant common difference of 3, making it arithmetic.
The nth term of a sequence is given by T_n = 2n² − n + 1. What is the value of T_4?
Answer: 29
T_4 = 2(4²) − 4 + 1 = 32 − 4 + 1 = 29.
A geometric series has first term 100 and common ratio 0.5. What is the sum to infinity?
Answer: 200
S∞ = a/(1 − r) = 100/(1 − 0.5) = 100/0.5 = 200.
In an arithmetic sequence, the 5th term is 17 and the 9th term is 33. What is the common difference?
Answer: 4
From a + 4d = 17 and a + 8d = 33, subtracting gives 4d = 16, so d = 4.