How to find the nth term of an arithmetic sequence - PSAT Math
Card 0 of 63
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
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The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
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We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.
We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.
Which of the following could not be a term in the sequence 5, 10, 15, 20...?
Which of the following could not be a term in the sequence 5, 10, 15, 20...?
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All answers in the sequence must end in a 5 or a 0.
All answers in the sequence must end in a 5 or a 0.
Consider the following sequence of numbers:
What will be the 8th term in the sequence?
Consider the following sequence of numbers:
What will be the 8th term in the sequence?
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Each number in the sequence in 7 more than the number preceding it.
The equation for the terms in an arithmetic sequence is an = a1 + d(n-1), where d is the difference.
The formula for the terms in this sequence is therefore an = 2 + 7(n-1).
Plug in 8 for n to find the 8th term:
a8 = 2 + 7(8-1) = 51
Each number in the sequence in 7 more than the number preceding it.
The equation for the terms in an arithmetic sequence is an = a1 + d(n-1), where d is the difference.
The formula for the terms in this sequence is therefore an = 2 + 7(n-1).
Plug in 8 for n to find the 8th term:
a8 = 2 + 7(8-1) = 51
In an arithmetic sequence, each term is two greater than the one that precedes it. If the sum of the first five terms of the sequence is equal to the difference between the first and fifth terms, what is the tenth term of the sequence?
In an arithmetic sequence, each term is two greater than the one that precedes it. If the sum of the first five terms of the sequence is equal to the difference between the first and fifth terms, what is the tenth term of the sequence?
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Let a1 represent the first term of the sequence and an represent the nth term.
We are told that each term is two greater than the term that precedes it. Thus, we can say that:
a2 = a1 + 2
a3 = a1 + 2 + 2 = a1 + 2(2)
a4 = a1 + 3(2)
a5 = a1 + 4(2)
an = a1 + (n-1)(2)
The problem tells us that the sum of the first five terms is equal to the difference between the fifth and first terms. Let's write an expression for the sum of the first five terms.
sum = a1 + (a1 + 2) + (a1 + 2(2)) + (a1 + 3(2)) + (a1 + 4(2))
= 5a1 + 2 + 4 + 6 + 8
= 5a1 + 20
Next, we want to write an expression for the difference between the fifth and first terms.
a5 - a1 = a1 + 4(2) – a1 = 8
Now, we set the two expressions equal and solve for a1.
5a1 + 20 = 8
Subtract 20 from both sides.
5a1 = –12
a1 = –2.4.
The question ultimately asks us for the tenth term of the sequence. Now, that we have the first term, we can find the tenth term.
a10 = a1 + (10 – 1)(2)
a10 = –2.4 + 9(2)
= 15.6
The answer is 15.6 .
Let a1 represent the first term of the sequence and an represent the nth term.
We are told that each term is two greater than the term that precedes it. Thus, we can say that:
a2 = a1 + 2
a3 = a1 + 2 + 2 = a1 + 2(2)
a4 = a1 + 3(2)
a5 = a1 + 4(2)
an = a1 + (n-1)(2)
The problem tells us that the sum of the first five terms is equal to the difference between the fifth and first terms. Let's write an expression for the sum of the first five terms.
sum = a1 + (a1 + 2) + (a1 + 2(2)) + (a1 + 3(2)) + (a1 + 4(2))
= 5a1 + 2 + 4 + 6 + 8
= 5a1 + 20
Next, we want to write an expression for the difference between the fifth and first terms.
a5 - a1 = a1 + 4(2) – a1 = 8
Now, we set the two expressions equal and solve for a1.
5a1 + 20 = 8
Subtract 20 from both sides.
5a1 = –12
a1 = –2.4.
The question ultimately asks us for the tenth term of the sequence. Now, that we have the first term, we can find the tenth term.
a10 = a1 + (10 – 1)(2)
a10 = –2.4 + 9(2)
= 15.6
The answer is 15.6 .
In a certain sequence, a n+1 = (an)2 – 1, where an represents the _n_th term in the sequence. If the third term is equal to the square of the first term, and all of the terms are positive, then what is the value of (_a_2)(_a_3)(_a_4)?
In a certain sequence, a n+1 = (an)2 – 1, where an represents the _n_th term in the sequence. If the third term is equal to the square of the first term, and all of the terms are positive, then what is the value of (_a_2)(_a_3)(_a_4)?
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Let _a_1 be the first term in the sequence. We can use the fact that a n+1 = (an)2 – 1 in order to find expressions for the second and third terms of the sequence in terms of _a_1.
_a_2 = (_a_1)2 – 1
_a_3 = (_a_2)2 – 1 = ((_a_1)2 – 1)2 – 1
We can use the fact that, in general, (a – b)2 = a_2 – 2_ab + _b_2 in order to simplify the expression for _a_3.
_a_3 = ((_a_1)2 – 1)2 – 1
= (_a_1)4 – 2(_a_1)2 + 1 – 1 = (_a_1)4 – 2(_a_1)2
We are told that the third term is equal to the square of the first term.
_a_3 = (_a_1)2
We can substitute (_a_1)4 – 2(_a_1)2 for _a_3.
(_a_1)4 – 2(_a_1)2 = (_a_1)2
Subtract (_a_1)2 from both sides.
(_a_1)4 – 3(_a_1)2 = 0
Factor out (_a_1)2 from both terms.
(_a_1)2 ((_a_1)2 – 3) = 0
This means that either (_a_1)2 = 0, or (_a_1)2 – 3 = 0.
If (_a_1)2 = 0, then _a_1 must be 0. However, we are told that all the terms of the sequence are positive. Therefore, the first term can't be 0.
Next, let's solve (_a_1)2 – 3 = 0.
Add 3 to both sides.
(_a_1)2 = 3
Take the square root of both sides.
_a_1 = ±√3
However, since all the terms are positive, the only possible value for _a_1 is √3.
Now, that we know that _a_1 = √3, we can find _a_2, _a_3, and _a_4.
_a_2 = (_a_1)2 – 1 = (√3)2 – 1 = 3 – 1 = 2
_a_3 = (_a_2)2 – 1 = 22 – 1 = 4 – 1 = 3
_a_4 = (_a_3)2 – 1 = 32 – 1 = 9 – 1 = 8
The question ultimately asks for the product of the _a_2, _a_3, and _a_4, which would be equal to 2(3)(8), or 48.
The answer is 48.
Let _a_1 be the first term in the sequence. We can use the fact that a n+1 = (an)2 – 1 in order to find expressions for the second and third terms of the sequence in terms of _a_1.
_a_2 = (_a_1)2 – 1
_a_3 = (_a_2)2 – 1 = ((_a_1)2 – 1)2 – 1
We can use the fact that, in general, (a – b)2 = a_2 – 2_ab + _b_2 in order to simplify the expression for _a_3.
_a_3 = ((_a_1)2 – 1)2 – 1
= (_a_1)4 – 2(_a_1)2 + 1 – 1 = (_a_1)4 – 2(_a_1)2
We are told that the third term is equal to the square of the first term.
_a_3 = (_a_1)2
We can substitute (_a_1)4 – 2(_a_1)2 for _a_3.
(_a_1)4 – 2(_a_1)2 = (_a_1)2
Subtract (_a_1)2 from both sides.
(_a_1)4 – 3(_a_1)2 = 0
Factor out (_a_1)2 from both terms.
(_a_1)2 ((_a_1)2 – 3) = 0
This means that either (_a_1)2 = 0, or (_a_1)2 – 3 = 0.
If (_a_1)2 = 0, then _a_1 must be 0. However, we are told that all the terms of the sequence are positive. Therefore, the first term can't be 0.
Next, let's solve (_a_1)2 – 3 = 0.
Add 3 to both sides.
(_a_1)2 = 3
Take the square root of both sides.
_a_1 = ±√3
However, since all the terms are positive, the only possible value for _a_1 is √3.
Now, that we know that _a_1 = √3, we can find _a_2, _a_3, and _a_4.
_a_2 = (_a_1)2 – 1 = (√3)2 – 1 = 3 – 1 = 2
_a_3 = (_a_2)2 – 1 = 22 – 1 = 4 – 1 = 3
_a_4 = (_a_3)2 – 1 = 32 – 1 = 9 – 1 = 8
The question ultimately asks for the product of the _a_2, _a_3, and _a_4, which would be equal to 2(3)(8), or 48.
The answer is 48.
You are given a sequence with the same difference between consecutive terms. We know it starts at 
and its 3rd term is 
. Find its 10th term.
You are given a sequence with the same difference between consecutive terms. We know it starts at
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From the given information, we know 
, which means each consecutive difference is 3.
From the given information, we know
The second and fourth terms of an arithmetic sequence are 9 and 18, respectively. What is its first term?
The second and fourth terms of an arithmetic sequence are 9 and 18, respectively. What is its first term?
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The difference between the second and fourth terms of an arithmetic sequence is twice the common difference - or, equivalently, the common difference is half the difference between the second and fourth terms.
The common difference can be subtracted from the second term to obtain the first term:
The difference between the second and fourth terms of an arithmetic sequence is twice the common difference - or, equivalently, the common difference is half the difference between the second and fourth terms.
The common difference can be subtracted from the second term to obtain the first term:
A sequence of numbers is represented by the equation 
, where 
represents the 
th term in the sequence. Which of the following equals the 
term in the sequence?
A sequence of numbers is represented by the equation
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Take the equation that represents the 
th term in the sequence and plug in the value of 9 for 
:
The value of the 9th term is 747.
Take the equation that represents the
The value of the 9th term is 747.
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
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The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
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We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.
We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.
Which of the following could not be a term in the sequence 5, 10, 15, 20...?
Which of the following could not be a term in the sequence 5, 10, 15, 20...?
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All answers in the sequence must end in a 5 or a 0.
All answers in the sequence must end in a 5 or a 0.
Consider the following sequence of numbers:
What will be the 8th term in the sequence?
Consider the following sequence of numbers:
What will be the 8th term in the sequence?
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Each number in the sequence in 7 more than the number preceding it.
The equation for the terms in an arithmetic sequence is an = a1 + d(n-1), where d is the difference.
The formula for the terms in this sequence is therefore an = 2 + 7(n-1).
Plug in 8 for n to find the 8th term:
a8 = 2 + 7(8-1) = 51
Each number in the sequence in 7 more than the number preceding it.
The equation for the terms in an arithmetic sequence is an = a1 + d(n-1), where d is the difference.
The formula for the terms in this sequence is therefore an = 2 + 7(n-1).
Plug in 8 for n to find the 8th term:
a8 = 2 + 7(8-1) = 51
In an arithmetic sequence, each term is two greater than the one that precedes it. If the sum of the first five terms of the sequence is equal to the difference between the first and fifth terms, what is the tenth term of the sequence?
In an arithmetic sequence, each term is two greater than the one that precedes it. If the sum of the first five terms of the sequence is equal to the difference between the first and fifth terms, what is the tenth term of the sequence?
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Let a1 represent the first term of the sequence and an represent the nth term.
We are told that each term is two greater than the term that precedes it. Thus, we can say that:
a2 = a1 + 2
a3 = a1 + 2 + 2 = a1 + 2(2)
a4 = a1 + 3(2)
a5 = a1 + 4(2)
an = a1 + (n-1)(2)
The problem tells us that the sum of the first five terms is equal to the difference between the fifth and first terms. Let's write an expression for the sum of the first five terms.
sum = a1 + (a1 + 2) + (a1 + 2(2)) + (a1 + 3(2)) + (a1 + 4(2))
= 5a1 + 2 + 4 + 6 + 8
= 5a1 + 20
Next, we want to write an expression for the difference between the fifth and first terms.
a5 - a1 = a1 + 4(2) – a1 = 8
Now, we set the two expressions equal and solve for a1.
5a1 + 20 = 8
Subtract 20 from both sides.
5a1 = –12
a1 = –2.4.
The question ultimately asks us for the tenth term of the sequence. Now, that we have the first term, we can find the tenth term.
a10 = a1 + (10 – 1)(2)
a10 = –2.4 + 9(2)
= 15.6
The answer is 15.6 .
Let a1 represent the first term of the sequence and an represent the nth term.
We are told that each term is two greater than the term that precedes it. Thus, we can say that:
a2 = a1 + 2
a3 = a1 + 2 + 2 = a1 + 2(2)
a4 = a1 + 3(2)
a5 = a1 + 4(2)
an = a1 + (n-1)(2)
The problem tells us that the sum of the first five terms is equal to the difference between the fifth and first terms. Let's write an expression for the sum of the first five terms.
sum = a1 + (a1 + 2) + (a1 + 2(2)) + (a1 + 3(2)) + (a1 + 4(2))
= 5a1 + 2 + 4 + 6 + 8
= 5a1 + 20
Next, we want to write an expression for the difference between the fifth and first terms.
a5 - a1 = a1 + 4(2) – a1 = 8
Now, we set the two expressions equal and solve for a1.
5a1 + 20 = 8
Subtract 20 from both sides.
5a1 = –12
a1 = –2.4.
The question ultimately asks us for the tenth term of the sequence. Now, that we have the first term, we can find the tenth term.
a10 = a1 + (10 – 1)(2)
a10 = –2.4 + 9(2)
= 15.6
The answer is 15.6 .
In a certain sequence, a n+1 = (an)2 – 1, where an represents the _n_th term in the sequence. If the third term is equal to the square of the first term, and all of the terms are positive, then what is the value of (_a_2)(_a_3)(_a_4)?
In a certain sequence, a n+1 = (an)2 – 1, where an represents the _n_th term in the sequence. If the third term is equal to the square of the first term, and all of the terms are positive, then what is the value of (_a_2)(_a_3)(_a_4)?
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Let _a_1 be the first term in the sequence. We can use the fact that a n+1 = (an)2 – 1 in order to find expressions for the second and third terms of the sequence in terms of _a_1.
_a_2 = (_a_1)2 – 1
_a_3 = (_a_2)2 – 1 = ((_a_1)2 – 1)2 – 1
We can use the fact that, in general, (a – b)2 = a_2 – 2_ab + _b_2 in order to simplify the expression for _a_3.
_a_3 = ((_a_1)2 – 1)2 – 1
= (_a_1)4 – 2(_a_1)2 + 1 – 1 = (_a_1)4 – 2(_a_1)2
We are told that the third term is equal to the square of the first term.
_a_3 = (_a_1)2
We can substitute (_a_1)4 – 2(_a_1)2 for _a_3.
(_a_1)4 – 2(_a_1)2 = (_a_1)2
Subtract (_a_1)2 from both sides.
(_a_1)4 – 3(_a_1)2 = 0
Factor out (_a_1)2 from both terms.
(_a_1)2 ((_a_1)2 – 3) = 0
This means that either (_a_1)2 = 0, or (_a_1)2 – 3 = 0.
If (_a_1)2 = 0, then _a_1 must be 0. However, we are told that all the terms of the sequence are positive. Therefore, the first term can't be 0.
Next, let's solve (_a_1)2 – 3 = 0.
Add 3 to both sides.
(_a_1)2 = 3
Take the square root of both sides.
_a_1 = ±√3
However, since all the terms are positive, the only possible value for _a_1 is √3.
Now, that we know that _a_1 = √3, we can find _a_2, _a_3, and _a_4.
_a_2 = (_a_1)2 – 1 = (√3)2 – 1 = 3 – 1 = 2
_a_3 = (_a_2)2 – 1 = 22 – 1 = 4 – 1 = 3
_a_4 = (_a_3)2 – 1 = 32 – 1 = 9 – 1 = 8
The question ultimately asks for the product of the _a_2, _a_3, and _a_4, which would be equal to 2(3)(8), or 48.
The answer is 48.
Let _a_1 be the first term in the sequence. We can use the fact that a n+1 = (an)2 – 1 in order to find expressions for the second and third terms of the sequence in terms of _a_1.
_a_2 = (_a_1)2 – 1
_a_3 = (_a_2)2 – 1 = ((_a_1)2 – 1)2 – 1
We can use the fact that, in general, (a – b)2 = a_2 – 2_ab + _b_2 in order to simplify the expression for _a_3.
_a_3 = ((_a_1)2 – 1)2 – 1
= (_a_1)4 – 2(_a_1)2 + 1 – 1 = (_a_1)4 – 2(_a_1)2
We are told that the third term is equal to the square of the first term.
_a_3 = (_a_1)2
We can substitute (_a_1)4 – 2(_a_1)2 for _a_3.
(_a_1)4 – 2(_a_1)2 = (_a_1)2
Subtract (_a_1)2 from both sides.
(_a_1)4 – 3(_a_1)2 = 0
Factor out (_a_1)2 from both terms.
(_a_1)2 ((_a_1)2 – 3) = 0
This means that either (_a_1)2 = 0, or (_a_1)2 – 3 = 0.
If (_a_1)2 = 0, then _a_1 must be 0. However, we are told that all the terms of the sequence are positive. Therefore, the first term can't be 0.
Next, let's solve (_a_1)2 – 3 = 0.
Add 3 to both sides.
(_a_1)2 = 3
Take the square root of both sides.
_a_1 = ±√3
However, since all the terms are positive, the only possible value for _a_1 is √3.
Now, that we know that _a_1 = √3, we can find _a_2, _a_3, and _a_4.
_a_2 = (_a_1)2 – 1 = (√3)2 – 1 = 3 – 1 = 2
_a_3 = (_a_2)2 – 1 = 22 – 1 = 4 – 1 = 3
_a_4 = (_a_3)2 – 1 = 32 – 1 = 9 – 1 = 8
The question ultimately asks for the product of the _a_2, _a_3, and _a_4, which would be equal to 2(3)(8), or 48.
The answer is 48.
You are given a sequence with the same difference between consecutive terms. We know it starts at and its 3rd term is . Find its 10th term.
You are given a sequence with the same difference between consecutive terms. We know it starts at
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From the given information, we know , which means each consecutive difference is 3.
From the given information, we know
The second and fourth terms of an arithmetic sequence are 9 and 18, respectively. What is its first term?
The second and fourth terms of an arithmetic sequence are 9 and 18, respectively. What is its first term?
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The difference between the second and fourth terms of an arithmetic sequence is twice the common difference - or, equivalently, the common difference is half the difference between the second and fourth terms.
The common difference can be subtracted from the second term to obtain the first term:
The difference between the second and fourth terms of an arithmetic sequence is twice the common difference - or, equivalently, the common difference is half the difference between the second and fourth terms.
The common difference can be subtracted from the second term to obtain the first term:
A sequence of numbers is represented by the equation , where represents the th term in the sequence. Which of the following equals the term in the sequence?
A sequence of numbers is represented by the equation
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Take the equation that represents the th term in the sequence and plug in the value of 9 for :
The value of the 9th term is 747.
Take the equation that represents the
The value of the 9th term is 747.
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
In the given sequence, the first term is 3 and each term after is one less than three times the previous term.
What is the sixth term in the sequence?
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The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
The fourth term is: 3(23) – 1 = 69 – 1 = 68.
The fifth term is: 3(68) – 1 = 204 – 1 = 203.
The sixth term is: 3(203) – 1 = 609 – 1 = 608.
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
2, 8, 14, 20
The first term in the sequence is 2, and each following term is determined by adding 6. What is the value of the 50th term?
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We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.
We start by multiplying 6 times 46, since the first 4 terms are already listed. We then add the product, 276, to the last listed term, 20. This gives us our answer of 296.