Precalculus : Functions

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #41 : 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 #42 : 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:  

Example Question #43 : Functions

Evaluate  for    .

 

Possible Answers:

Correct answer:

Explanation:

We evaluate the function when .

Example Question #41 : Functions

Find the domain of f(x) below

Possible Answers:

Correct answer:

Explanation:

We have We have for all real numbers.  when . The denominator is undefined when .

The nominator is defined if .

The domain is:

Example Question #41 : Functions

The domain of the following function

 

is:

Possible Answers:

Correct answer:

Explanation:

is defined when . Since we do not want  to be 0 in the denominator we must have . when x=2.

Thus we need to exclude 2 also. Therefore the domain is:

Example Question #46 : Functions

Find the range of the following function:

Possible Answers:

Correct answer:

Explanation:

Every element of the domain has as image 7.This means that the function is constant . Therefore,

the range of f is :{7}.

Example Question #43 : Functions

What is the domain of the following function:

Possible Answers:

 

 

Correct answer:

Explanation:

Note that in the denominator, we need to have to make the square root of x defined. In this case  is never zero. Hence we have no issue when dividing by this number. Therefore the domain is the set of real numbers that are

 

Example Question #42 : Functions

Find the domain of the following function f(x) given below:

Possible Answers:

Correct answer:

Explanation:

 

. Since  for all real numbers. To make the square root positive we need to have .

Therefore the domain is :

 

 

 

Example Question #43 : Functions

What is the range of :

Possible Answers:

Correct answer:

Explanation:

We know that . So .

Therefore:

.

This gives:

.

Therefore the range is:

Example Question #46 : Functions

Find the range of f(x) given below:

Possible Answers:

Correct answer:

Explanation:

Note that: we can write f(x) as :

.

Since,

Therefore,

So the range is

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