High School Math : Pre-Calculus

Study concepts, example questions & explanations for High School Math

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Example Questions

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:

Example Question #2 : 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.

 

Example Question #1 : Finding Partial Sums In A Series

Find the sum of the even integers from  to .

Possible Answers:

Correct answer:

Explanation:

The sum of even integers represents an arithmetic series.

The formula for the partial sum of an arithmetic series is

,

where  is the first value in the series,  is the number of terms, and  is the difference between sequential terms.

Plugging in our values, we get:

Example Question #1 : Sums Of Infinite Series

Find the value for 

Possible Answers:

Correct answer:

Explanation:

To best understand, let's write out the series. So

We can see this is an infinite geometric series with each successive term being multiplied by .

A definition you may wish to remember is

 where  stands for the common ratio between the numbers, which in this case is  or . So we get

 

Example Question #1 : Sums Of Infinite Series

Evaluate:

Possible Answers:

The series does not converge.

Correct answer:

Explanation:

This is a geometric series whose first term is   and whose common ratio is . The sum of this series is:

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