Precalculus : Exponential and Logarithmic Functions

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #62 : Properties Of Logarithms

Express the following in expanded form.

Possible Answers:

Correct answer:

Explanation:

To solve, simply remember that when adding logs, you multiply their insides and when subtract logs, you divide your insides. You must use this in reverse to solve. Thus,

Example Question #37 : Solve Logarithmic Equations

Completely expand this logarithm: 

Possible Answers:

The answer is not present.

Correct answer:

Explanation:

We expand logarithms using the same rules that we use to condense them.

Here we will use the quotient property  

 

and the power property  

Use the quotient property:

Rewrite the radical:

Now use the power property:

 

 

Example Question #63 : Properties Of Logarithms

Expand the logarithm 

 

Possible Answers:

Correct answer:

Explanation:

In order to expand the logarithmic expression, we use the following properties

As such

Example Question #64 : Properties Of Logarithms

Given the equation , what is the value of ? Use the inverse property to aid in solving.

Possible Answers:

Correct answer:

Explanation:

The natural logarithm and natural exponent are inverses of each other.  Taking the  of  will simply result in the argument of the exponent. 

That is

Now, , so

Example Question #1 : Graph Logarithms

What is the domain of the function 

Possible Answers:

Correct answer:

Explanation:

The function  is undefined unless . Thus  is undefined unless  because the function has been shifted left. 

Example Question #2 : Graph Logarithms

What is the range of the function 

Possible Answers:

Correct answer:

Explanation:

To find the range of this particular function we need to first identify the domain. Since  we know that  is a bound on our function.

From here we want to find the function value as  approaches .

To find this approximate value we will plug in  into our original function.

This is our lowest value we will obtain. As we plug in large values we get large function values.

Therefore our range is:

 

Example Question #3 : Graph Logarithms

Which of the following logarithmic functions match the provided diagram?

Varsity log graph

Possible Answers:

Correct answer:

Explanation:

Looking at the diagram, we can see that when . Since  represents the exponent and  represents the product, and any base with an exponent of 1 equals the base, we can determine the base to be 0.5. 

Example Question #4 : Graph Logarithms

Which of the following diagrams represents the graph of the following logarithmic function?

Possible Answers:

Varsity log graph

Varsity log graph

Varsity log graph

Varsity log graph

Varsity log graph

Correct answer:

Varsity log graph

Explanation:

For ,  is the exponent of base 5 and  is the product. Therefore, when  and when . As a result, the correct graph will have  values of 5 and 125 at  and , respectively. 

Example Question #4 : Graph Logarithms

Which of the following diagrams matches the given logarithmic function:

Possible Answers:

Varsity log graph

Varsity log graph

Varsity log graph

Varsity log graph

Varsity log graph

Correct answer:

Varsity log graph

Explanation:

For this function,  represents the exponent and y represents the product of the base 2 and its exponent. On the diagram, it is clear that as the  value increases, the  value increases exponentially and at , . Those two characteristics of the graph indicate that x is the exponent value and the base is equal to 2. 

Example Question #5 : Graph Logarithms

Which of the following logarithmic functions match the given diagram?

Varsity log graph

Possible Answers:

Correct answer:

Explanation:

Looking at the graph, the y-value diminishes exponentially as  decreases and increases rapidly as the x-value increases, which indicates that  is the exponent value for the equation.

Also,  when  and  when , which can be expressed as  and , respectively.

This indicates that the diagram is consistent with the function .

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