Precalculus : Relations and Functions

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #21 : Functions

What is the domain of the following function?

Possible Answers:

-

Correct answer:

Explanation:

The denominator becomes zero whenever cos(x) becomes -1 and this happens when x is an odd multiple of .  To avoid division by zero, we exclude all these numbers. Therefore the domain is:

 

Example Question #31 : Functions

Given  and , evaluate .

Possible Answers:

Correct answer:

Explanation:

We are given two functions and asked to find f(h(7)).

I would begin by finding h(7)

Now that we know h(7), we go ahead and plug it into f(x).

So our final answer is simply 8.

Example Question #32 : Functions

Solve the function.  

Possible Answers:

Correct answer:

Explanation:

Determine the domain of .

Multiply  on both sides of the equation to cancel the denominator and divide the equation  by ten.

Since the domain states that , the only possible answer is .

Example Question #3 : Evaluate Functions

Solve for :  

Possible Answers:

Correct answer:

Explanation:

Rewrite  so that the exponential variable is isolated.

Reconvert  to a similar base.  Use exponents to redefine the terms.

Since all terms are of the same base, use the property of log to eliminate the base on both sides of the equation.

Solve for .

Example Question #1 : Evaluate Functions

Evaluate the following function when 

Possible Answers:

Correct answer:

Explanation:

Evaluate the following function when 

To evaluate this function, simply plug-in 6 for t and simplify:

So our answer is:

Example Question #1 : Evaluate Functions

Determine the value of  of the function

Possible Answers:

Correct answer:

Explanation:

In order to determine the value of  of the function we set  The value becomes

As such

Example Question #1 : Evaluate Functions

Find the difference quotient of the function .

Possible Answers:

Correct answer:

Explanation:

Difference quotient equation is 

 and 

.

Now plug in the appropriate terms into the equation and simplify:

Example Question #1 : Evaluate Functions

Find the value of the following function when 

Possible Answers:

The function is undefined at 

Correct answer:

The function is undefined at 

Explanation:

Find the value of the following function when 

To evaluate this function, plug in 2 for x everywhere it arises and simplify:

So our answer must be undefined, because we cannot divide by 

Example Question #8 : Evaluate Functions

Find the value of  when 

 

Possible Answers:

Correct answer:

Explanation:

Find the value of  when 

 

To evaluate this expression, plug in the given value of  everywhere you see a  and simplify:

So our answer is:

 

Example Question #9 : Evaluate Functions

If , what is ?

Possible Answers:

Correct answer:

Explanation:

In order to evaluate this function, simply substitute the value of  as a replacement of .

Simplify using the order of operations.

The answer is:  

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