Sequences flashcards

24 practice cards drawn from the Sequences lessons. Tap a card to turn it over. Every answer is checked against the lesson it came from.

Read the Sequences lessons in full →

8, 17, 26, 35, … what comes next?

44

from “Term-to-Term Rules”

4, 9, 14, 19, … what comes next?

24

from “Term-to-Term Rules”

2, 8, 14, 20, … what is the nth term?

6n − 4

from “The nth Term”

7, 16, 25, 34, … what is the nth term?

9n − 2

from “The nth Term”

1, 1, 2, 3, 5, 8, 13, … what comes next?

21

from “Sequences Worth Knowing”

1, 1, 2, 3, 5, 8, … what comes next?

13

from “Sequences Worth Knowing”

2, 6, 12, 20, … the coefficient is…?

1

from “Quadratic Sequences”

3, 8, 15, 24, … what comes next?

35

from “Quadratic Sequences”

2, 6, 18, 54, … what comes next?

162

from “Geometric Sequences”

2, 4, 8, … — what is term 6?

64

from “Geometric Sequences”

Work out Σ 2n, from n = 1 to 4

20

from “Sigma Notation”

Work out Σ 2n, from n = 1 to 5

30

from “Sigma Notation”

Folding 1 + 2 + … + 10 works because…

ends paired inward all make the same total

from “The Sum of an Arithmetic Series”

2 + 4 + 6 + … + 20 has 10 terms. What is its sum?

110

from “The Sum of an Arithmetic Series”

What is 1 + 3 + 9?

13

from “The Sum of a Geometric Series”

What is 4 + 12 + 36?

52

from “The Sum of a Geometric Series”

First term 12, ratio 1/4. What is S∞?

16

from “The Sum to Infinity”

A geometric series has a sum to infinity when…

its ratio sits strictly between −1 and 1

from “The Sum to Infinity”

The rule "each term is the one before plus 4" cannot start without…

the first term

from “Recurrence Relations”

u₁ = 2, and each term is the one before plus 5. What is u₃?

12

from “Recurrence Relations”

What is 1 + 2 + … + 12?

78

from “Proof by Induction: Summing 1 to n”

What is 1 + 2 + … + 18?

171

from “Proof by Induction: Summing 1 to n”

How does this differ from proving a summation formula?

the step compares consecutive cases

from “Proof by Induction: Divisibility”

For f(n) = 3²ⁿ + 11, what is f(k + 1) − f(k)?

8 × 3²ᵏ

from “Proof by Induction: Divisibility”

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