High School Math : Sequences and Series

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : Using Sigma Notation

Indicate the sum of the following series.

Possible Answers:

Correct answer:

Explanation:

The formula for the sum of a geometric series is

,

where  is the first term in the series,  is the rate of change between sequential terms, and  is the number of terms in the series

In this problem we have:

Plugging in our values, we get:

Example Question #1 : Terms In A Series

Consider the sequence:

What is the fifteenth term in the sequence?

Possible Answers:

Correct answer:

Explanation:

The sequence can be described by the equation , where is the term in the sequence.

For the 15th term, .

Example Question #2 : Finding Terms In A Series

What are the first three terms in the series?

Possible Answers:

Correct answer:

Explanation:

To find the first three terms, replace  with , and .

The first three terms are , and .

Example Question #3 : Finding Terms In A Series

Find the first three terms in the series.

Possible Answers:

Correct answer:

Explanation:

To find the first three terms, replace  with , and .

The first three terms are , and .

Example Question #1 : Finding Terms In A Series

Indicate the first three terms of the following series:

Possible Answers:

Correct answer:

Explanation:

In the arithmetic series, the first terms can be found by plugging , and  into the equation.

 

 

 

Example Question #41 : Pre Calculus

Indicate the first three terms of the following series:

Possible Answers:

Correct answer:

Explanation:

In the arithmetic series, the first terms can be found by plugging in , and  for .

 

 

 

Example Question #1 : Finding Terms In A Series

Indicate the first three terms of the following series:

Possible Answers:

Correct answer:

Explanation:

The first terms can be found by substituting , and  for  into the sum formula.

 

 

 

Example Question #1 : Finding Terms In A Series

Indicate the first three terms of the following series.

Possible Answers:

Not enough information

Correct answer:

Explanation:

The first terms can be found by substituting , and  in for .

 

 

 

Example Question #8 : Finding Terms In A Series

What is the sixth term when  is expanded?

Possible Answers:

Correct answer:

Explanation:

We will need to use the Binomial Theorem in order to solve this problem. Consider the expansion of , where n is an integer. The rth term of this expansion is given by the following formula:

,

 where  is a combination. In general, if x and y are nonnegative integers such that x > y, then the combination of x and y is defined as follows: .

We are asked to find the sixth term of , which means that in this case r = 6 and n = 10. Also, we will let  and . We can now apply the Binomial Theorem to determine the sixth term, which is as follows:

 

Next, let's find the value of . According to the definition of a combination, 

.

Remember that, if n is a positive integer, then . This is called a factorial. 

Let's go back to simplifying .

 

 

The answer is .

 

Example Question #1 : Finding Partial Sums In A Series

Find the sum of all even integers from  to .

Possible Answers:

Correct answer:

Explanation:

The formula for the sum of an arithmetic series is

,

where  is the number of terms in the series,  is the first term, and  is the last term.

We know that there are  terms in the series. The first term is  and the last term is . Our formula becomes:

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