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Example Questions
Example Question #1 : How To Find The Nth Term Of An Arithmetic Sequence
Find the 100th term in the following arithmetic sequence
Before we can figure out the 100th term, we need to find a rule for this arithmetic sequence. Remember, the general rule for this sequence is
where represents the first number in the sequence, is the common difference between consecutive numbers, and is the -th number in the sequence.
In our problem, . Also, each time we move up from one number to another, the number increases by 7. Therefore, . So the rule for this sequence is written as
Now that we found our rule, we can go on and figure out what the 100th term is equal to. For the 100th term, . Thus
Example Question #8 : How To Find The Nth Term Of An Arithmetic Sequence
To find any term of an arithmetic sequence:
Where is the first term, is the number of the term to find, and is the common difference in the sequence.
Find the 18th term of the following arithmetic sequence.
Start by finding the common difference, , in this sequence, which you can get by subtracting the first term from the second.
Then, using the formula given before the question:
Example Question #9 : How To Find The Nth Term Of An Arithmetic Sequence
To find any term of an arithmetic sequence:
Where is the first term, is the number of the term to find, and is the common difference in the sequence.
Find the 26th term of the following arithmetic sequence.
Start by finding the common difference in terms by subtracting the first term from the second.
Then, fill in the rest of the equation given before the question.
Example Question #1 : How To Find The Nth Term Of An Arithmetic Sequence
Given the the sequence below, what is the 11th term of the sequence?
1, 5, 9, 13, . . .
45
49
53
41
37
41
The 11th term means there are 10 gaps in between the first term and the 11th term. Each gap has a difference of +4, so the 11th term would be given by 10 * 4 + 1 = 41.
The first term is 1.
Each term after increases by +4.
The nth term will be equal to 1 + (n – 1)(4).
The 11th term will be 1 + (11 – 1)(4)
1 + (10)(4) = 1 + (40) = 41
Example Question #11 : How To Find The Nth Term Of An Arithmetic Sequence
The second term of an arithmetic sequence is ; the fourth term is . What is the first term?
The common difference between the terms is half that between the second and fourth terms - that is:
Subtract this common difference from the second term to get the first:
Example Question #12 : How To Find The Nth Term Of An Arithmetic Sequence
An arithmetic sequence is given by the formula . What is the difference between and
You can either calculate the vaules of and and subtract, or notice from the formula that each succesive number in the sequence is 3 larger than the previous
Example Question #11 : Arithmetic Series
Consider the following arithmetic sequence:
What is the term?
A simple way to find the term of an arithmetic sequence is to use the formula .
Here, is the term you are trying to find, is the first term, and is the common difference. For this question, the common difference is .
Example Question #14 : How To Find The Nth Term Of An Arithmetic Sequence
What is the 20th term of ?
Notice that every odd term is increasing at an increment of , since the numbers are . We will ignore these terms and concentrate on only the even terms.
The even terms are for the second, fourth, and sixth terms respectively, which means that the numbers are a multiple of nine.
The equation that represents the terms for this sequence is: , for even terms since it only applies to the even terms that are divisible by nine and occurs after every two terms.
Substitute to determine the 20th term.
The answer is:
Example Question #31 : Sequences
What is the 11th term in the following sequence?
First we need to show how this sequence is changing. Let's call the first number, and the second number , and so on.
Ok, so we have established that the sequence is shrinking by 9 each time. So now we need to calculate out to the 11th term. Starting from the first term, we need to subtract 9 ten times to get to the 11th term. So that would look like this.
Example Question #11 : Arithmetic Series
Which of the following is an example of an arithmetic sequence?
Each of these sequences is an arithmetic sequence.
Each of these sequences is an arithmetic sequence.
In each case, the terms increase by the same number, so all of these sequences are arithmetic.
Each term is the result of adding 1 to the previous term. 1 is the common difference.
Each term is the result of subtracting 1 from - or, equivalently, adding to - the previous term. is the common difference.
The common difference is 0 in a constant sequence such as this.
Each term is the result of adding to the previous term. is the common difference.
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