Mathematics
Grade 11
15 min
Sequences: mixed review
Sequences: mixed review
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1
Introduction & Learning Objectives
Learning Objectives
Distinguish between arithmetic, geometric, and other types of sequences.
Determine the common difference or common ratio from a given sequence.
Write the explicit formula for the nth term of an arithmetic or geometric sequence.
By the end of a this lesson, students will be able to calculate the value of a specific term (a_n) in a sequence.
Solve for the number of terms (n) in a finite sequence.
Determine the formula for a sequence given two non-consecutive terms.
If a bouncing ball returns to 80% of its previous height with each bounce, can you predict how high it will be on its 10th bounce? 🧐
This tutorial is a mixed review of arithmetic and geometric sequences. You will learn to identify different sequence types, apply the correct formulas to solve fo...
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Key Concepts & Vocabulary
TermDefinitionExample
SequenceAn ordered list of numbers, called terms, that follow a specific pattern or rule.3, 7, 11, 15, ... is a sequence where each term is 4 more than the previous one.
Arithmetic SequenceA sequence in which the difference between consecutive terms is constant. This constant is called the common difference (d).The sequence 5, 2, -1, -4, ... is arithmetic because the common difference is -3 (2 - 5 = -3).
Geometric SequenceA sequence in which the ratio between consecutive terms is constant. This constant is called the common ratio (r).The sequence 2, 6, 18, 54, ... is geometric because the common ratio is 3 (6 / 2 = 3).
Term (a_n)An individual number in a sequence. `a_n` refers to the term in the nth position, where `a_1` is the first term.In the sequence 10, 20, 30,...
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Core Formulas
Nth Term of an Arithmetic Sequence
a_n = a_1 + (n-1)d
Use this formula to find any term (`a_n`) of an arithmetic sequence when you know the first term (`a_1`), the term's position (`n`), and the common difference (`d`).
Nth Term of a Geometric Sequence
a_n = a_1 * r^(n-1)
Use this formula to find any term (`a_n`) of a geometric sequence when you know the first term (`a_1`), the term's position (`n`), and the common ratio (`r`).
4 more steps in this tutorial
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Challenging
The 4th term of a geometric sequence is 54 and the 7th term is 1458. What is the 10th term?
A.39366
B.13122
C.4374
D.2916
Challenging
An arithmetic sequence has a_7 = 10 and a_{16} = 46. For what value of n is a_n = 70?
A.n = 22
B.n = 24
C.n = 25
D.n = 28
Challenging
A theater's seats are arranged so that the first row has 10 seats, the second has 13, the third has 16, and so on. If the last row has 61 seats, how many rows are in the theater?
A.16
B.17
C.18
D.19
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