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Example Questions
Example Question #11 : Sigma Notation
What is the proper sigma sum notation of the summation of ?
Given that the first term of the sequence is , we know that the first term of the summation must be , and thus the lower bound of summation must be equal to There is only one option with this qualification, and so we have our answer.
Example Question #1 : Finding Terms In A Series
Consider the sequence:
What is the fifteenth term in the sequence?
The sequence can be described by the equation , where is the term in the sequence.
For the 15th term, .
Example Question #1 : Terms In A Series
What is the sum of the first terms of an arithmetic series if the first term is , and the last term is ?
Write the formula to find the arithmetic sum of a series where is the number of terms, is the first term, and is the last term.
Substitute the given values and solve for the sum.
Example Question #3 : Terms In A Series
Given the terms of the sequence , what are the next two terms after ?
The next two terms are and . This is the Fibonacci sequence where you start off with the terms and , and the next term is the sum of two previous terms. So then
and so on.
Example Question #1 : Terms In A Series
What is the fifth term of the series
Let's try to see if this series is a geometric series.
We can divide adjacent terms to try and discover a multiplicative factor.
Doing this it seems the series proceeds with a common multiple of between each term.
Rewriting the series we get,
.
When
.
Example Question #181 : Pre Calculus
What is the 9th term of the series that begins 2, 4, 8, 16...
256
1024
144
512
488
512
In this geometric series, each number is created by multiplying the previous number by 2. You may also see that, because the first number is 2, it also becomes a list of powers of 2. The list is 2, 4, 8, 16, 32, 64, 128, 256, 512, where you can see that the 9th term is 512.
Example Question #31 : Sequences And Series
What is the 10th term in the series:
1, 5, 9, 13, 17....
37
23
45
31
41
37
The pattern in this arithmetic series is that each term is created by adding 4 to the previous one. You can then continue the series by continuing to add 4s until you've gotten to the tenth term:
1, 5, 9, 13, 17, 21, 25, 29, 33, 37
The correct answer, then, is 37.
Example Question #1 : Partial Sums Of Series
For the sequence
Determine .
is defined as the sum of the terms from to
Therefore, to get the solution we must add all the entries from from to as follows.
Example Question #2 : Partial Sums Of Series
Simplify the sum.
The answer is . Try this for :
This can be proven more generally using a proof technique called mathematical induction, which you will most likely not learn in high school.
Example Question #3 : Partial Sums Of Series
In case you are not familiar with summation notation, note that:
Given the series above, what is the value of ?
Since the upper bound of the iterator is and the initial value is , we need add one-half, the summand, six times.
This results in the following arithmetic.
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