High School Math : Pre-Calculus

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : Simplifying Polynomial Functions

Simplify the following polynomial function:

Possible Answers:

Correct answer:

Explanation:

First, multiply the outside term with each term within the parentheses:

Rearranging the polynomial into fractional form, we get:

Example Question #1 : Solving Logarithms

You are given that  and 

Which of the following is equal to  ?

Possible Answers:

Correct answer:

Explanation:

Since  and , it follows that  and 

Example Question #21 : Pre Calculus

Possible Answers:

Correct answer:

Explanation:

Example Question #2 : Solving Logarithms

What is 

Possible Answers:

Correct answer:

Explanation:

Recall that by definition a logarithm is the inverse of the exponential function. Thus, our logarithm corresponds to the value of  in the equation: 

We know that  and thus our answer is .

Example Question #1 : Simplifying Logarithms

Solve for

Possible Answers:

The correct solution set is not included among the other choices.

Correct answer:

The correct solution set is not included among the other choices.

Explanation:

FOIL: 

These are our possible solutions. However, we need to test them.

 

:

 

The equation becomes . This is true, so  is a solution.

 

:

 

However, negative numbers do not have logarithms, so this equation is meaningless.  is not a solution, and  is the one and only solution. Since this is not one of our choices, the correct response is "The correct solution set is not included among the other choices."

Example Question #1 : Simplifying Exponential Functions

Possible Answers:

Correct answer:

Explanation:

Example Question #1 : Sequences And Series

Evaluate: 

Possible Answers:

None of the other answers are correct.

Correct answer:

Explanation:

This sum can be determined using the formula for the sum of an infinite geometric series, with initial term  and common ratio :

Example Question #1 : Arithmetic And Geometric Series

The fourth term in an arithmetic sequence is -20, and the eighth term is -10. What is the hundredth term in the sequence?

Possible Answers:

220

110

55

105

210

Correct answer:

220

Explanation:

An arithmetic sequence is one in which there is a common difference between consecutive terms. For example, the sequence {2, 5, 8, 11} is an arithmetic sequence, because each term can be found by adding three to the term before it. 

Let  denote the nth term of the sequence. Then the following formula can be used for arithmetic sequences in general:

, where d is the common difference between two consecutive terms. 

We are given the 4th and 8th terms in the sequence, so we can write the following equations:

.

We now have a system of two equations with two unknowns:

Let us solve this system by subtracting the equation  from the equation . The result of this subtraction is

.

This means that d = 2.5.

Using the equation , we can find the first term of the sequence.

Ultimately, we are asked to find the hundredth term of the sequence.

The answer is 220.

Example Question #1 : Sequences And Series

Find the sum, if possible:

Possible Answers:

Correct answer:

Explanation:

The formula for the summation of an infinite geometric series is

,

where  is the first term in the series and  is the rate of change between succesive terms.  The key here is finding the rate, or pattern, between the terms.  Because this is a geometric sequence, the rate is the constant by which each new term is multiplied. 

Plugging in our values, we get:

Example Question #2 : Sequences And Series

Find the sum, if possible:

Possible Answers:

Correct answer:

Explanation:

The formula for the summation of an infinite geometric series is

,

where  is the first term in the series and  is the rate of change between succesive terms in a series

Because the terms switch sign, we know that the rate must be negative. 

Plugging in our values, we get:

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