Precalculus : Functions

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #41 : Inverse Functions

Find the inverse function of .

Possible Answers:

None of the other answers.

Correct answer:

Explanation:

To find the inverse you must reverse the variables and solve for y.

Reverse the variables:

Solve for y:

Example Question #42 : Inverse Functions

Are these two function inverses?   and  .

Possible Answers:

Yes

F(x) does not have an inverse.

Cannot tell 

G(x) does not have an inverse.

No

Correct answer:

Yes

Explanation:

One can ascertain if two functions have an inverse by finding the composition of both functions in turn. Each composition should equal x if the functions are indeed inverses of each other.

The functions are inverses of each other.

Example Question #43 : Inverse Functions

Find the inverse of the following equation:

Possible Answers:

Correct answer:

Explanation:

To find the inverse of a function, replace the x any y positions:

Original Equation: 

Inversed Equation:  

Now solve for the inversed y value.

Example Question #37 : Find The Inverse Of A Function

Find the inverse of the following equation:

Possible Answers:

Correct answer:

Explanation:

To find the inverse of a function, replace the x any y positions:

Original Equation: 

Inversed Equation:  

Now solve for the inversed y value.

Example Question #38 : Find The Inverse Of A Function

Find the inverse of the following equation:

Possible Answers:

Correct answer:

Explanation:

To find the inverse of a function, replace the x any y positions:

Original Equation: 

Inversed Equation:  

Now solve for the inversed y value.

Example Question #122 : Functions

Determine the inverse function, given 

 

Possible Answers:

Correct answer:

Explanation:

In order to find the inverse function we 

  1. switch the variables  and 
  2. solve for the new  variable

For the function

 ...

Hence, the inverse function is

Example Question #1 : Plot Points

The point  is in which quadrant?

Possible Answers:

Lies on an axis

III

II

I

IV

Correct answer:

III

Explanation:

In order to determine in which quadrant the point lies, we must remember the order of the quadrants. The first quadrant is that where x and y are both positive, to the upper right of the origin. To move sequentially to the final quadrant, we go counterclockwise from the first quadrant, which means the second is where x is negative and y is positive, the third is where x and y are both negative, and the fourth is where x is positive and y is negative. We can see from our point (-3,-8) that x and y are both negative, which means the point lies in the third quadrant. 

Example Question #2 : Cartesian Coordinate System

 and  are located on the circle, with  forming its diameter. What is the area of the circle. 

Possible Answers:

Correct answer:

Explanation:

Use the distance formula to find the length of 

.

Since the length of  is that of the diameter, the radius of the circle is .

Thus, the area of the circle is 

.

Example Question #3 : Plot Points

Which of the following coordinates does NOT fit on the graph of the corresponding function?

Varsity practice precalc

Possible Answers:

Correct answer:

Explanation:

When looking at the graph, it is clear that when ,  has a value less than . If we were to plug in the value of , our equation would come out as such:

Therefore, at , we get a , providing the coordinate .

Example Question #4 : Plot Points

Which of the following  coordinates does NOT correspond with the given function and graph?

Varsity practice precalc

Possible Answers:

Correct answer:

Explanation:

When looking at the graph, it is clear that when ,  has a value greater than . When we plug in both  and  values into the function, it is clear that these values do not work for the function:

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