High School Math : Pre-Calculus

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : Function Properties

What is the domain of the function below:

 

Possible Answers:

Correct answer:

Explanation:

The domain is defined as the set of all possible values of the independent variable . First,  must be greater than or equal to zero, because if , thenwill be undefined. In addition, the total expression under the radical, i.e.  must be greater than or equal to zero:

 

 

That means that the expression under the radical is always positive and therefore is defined. Hence, the domain of the function is .

Example Question #12 : Pre Calculus

This function is:

Possible Answers:

not symmetric

symmetric about the x-axis

symmetric about the origin

symmetric about the y-axis

Correct answer:

symmetric about the y-axis

Explanation:

A function's symmetry is related to its classification as even, odd, or neither.

Even functions obey the following rule:

Because of this, even functions are symmetric about the y-axis.

Odd functions obey the following rule:

Because of this, odd functions are symmetric about the origin.

If a function does not obey either rule, it is neither odd nor even. (A graph that is symmetric about the x-axis is not a function, because it does not pass the vertical line test.)

To test for symmetry, simply substitute into the original equation.

Thus, this equation is even and therefore symmetric about the y-axis.

Example Question #1 : Finding Asymptotes

A function is defined by the following rational equation:

What are the horizontal and vertical asymptotes of this function's graph?

Possible Answers:

Correct answer:

Explanation:

To find the horizontal asymptote, compare the degrees of the top and bottom polynomials. In this case, the two degrees are the same (1), which means that the equation of the horizontal asymptote is equal to the ratio of the leading coefficients (top : bottom). Since the numerator's leading coefficient is 1, and the denominator's leading coefficient is 2, the equation of the horizontal asymptote is .

 

To find the vertical asymptote, set the denominator equal to zero to find when the entire function is undefined:

Example Question #2 : Finding Asymptotes

A function is defined by the following rational equation:

What line does approach as approaches infinity?

Possible Answers:

Correct answer:

Explanation:

This question is asking for the equation's slant asymptote. To find the slant asymptote, divide the numerator by the denominator. Long division gives us the following:

However, because we are considering  as it approaches infinity, the effect that the last term has on the overall linear equation quickly becomes negligible (tends to zero). Thus, it can be ignored.

Example Question #13 : Pre Calculus

Factor the polynomial if the expression is equal to zero when .

Possible Answers:

Correct answer:

Explanation:

Knowing the zeroes makes it relatively easy to factor the polynomial.

The expression fits the description of the zeroes.

Now we need to check the answer.

We are able to get back to the original expression, meaning that the answer is .

Example Question #14 : Pre Calculus

A polyomial with leading term  has 6 as a triple root. What is this polynomial?

Possible Answers:

 

Correct answer:

Explanation:

Since 6 is a triple root, and the degree of the polynomial is 3, the polynomial is , which we can expland using the cube of a binomial pattern.

Example Question #1 : Express A Polynomial As A Product Of Linear Factors

A polyomial with leading term  has 5 and 7 as roots; 7 is a double root. What is this polynomial?

Possible Answers:

Correct answer:

Explanation:

Since 5 is a single root and 7 is a double root, and the degree of the polynomial is 3, the polynomial is . To put this in expanded form:

 

Example Question #1 : Understanding Zeros Of A Polynomial

What are the solutions to  ? 

Possible Answers:

Correct answer:

Explanation:

When we are looking for the solutions of a quadratic, or the zeroes, we are looking for the values of  such that the output will be zero. Thus, we first factor the equation. 

Then, we are looking for the values where each of these factors are equal to zero. 

 implies 

and  implies 

Thus, these are our solutions. 

Example Question #15 : Pre Calculus

Find the zeros of the following polynomial:

Possible Answers:

Correct answer:

Explanation:

First, we need to find all the possible rational roots of the polynomial using the Rational Roots Theorem:

Since the leading coefficient is just 1, we have the following possible (rational) roots to try:

±1, ±2, ±3, ±4, ±6, ±12, ±24

When we substitute one of these numbers for , we're hoping that the equation ends up equaling zero. Let's see if  is a zero:

Since the function equals zero when  is , one of the factors of the polynomial is . This doesn't help us find the other factors, however. We can use synthetic substitution as a shorter way than long division to factor the equation.

            

      

Now we can factor the function this way:

We repeat this process, using the Rational Roots Theorem with the second term to find a possible zero. Let's try :

When we factor using synthetic substitution for , we get the following result:

Using our quadratic factoring rules, we can factor completely:

Thus, the zeroes of  are

Example Question #16 : Pre Calculus

Simplify the following polynomial:

Possible Answers:

Correct answer:

Explanation:

To simplify the polynomial, begin by combining like terms:

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