SAT II Math II : Functions and Graphs

Study concepts, example questions & explanations for SAT II Math II

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Example Questions

Example Question #1 : Graphing Functions

Give the amplitude of the graph of the function

Possible Answers:

Correct answer:

Explanation:

The amplitude of the graph of a sine function  is . Here, , so this is the amplitude.

Example Question #2 : Graphing Functions

Which of these functions has a graph with amplitude 4?

Possible Answers:

Correct answer:

Explanation:

The functions in each of the choices take the form of a cosine function 

.

The graph of a cosine function in this form has amplitude . Therefore, for this function to have amplitude 4, . Of the five choices, only 

matches this description.

Example Question #2 : Graphing Trigonometric Functions

Which of these functions has a graph with amplitude  ?

Possible Answers:

Correct answer:

Explanation:

The functions in each of the choices take the form of a sine function 

.

The graph of a sine function in this form has amplitude . Therefore, for this function to have amplitude 4, . Of the five choices, only 

matches this description.

Example Question #4 : Graphing Trigonometric Functions

Which of the following sine functions has a graph with period of 7?

Possible Answers:

Correct answer:

Explanation:

The period of the graph of a sine function , is , or .

Therefore, we solve for :

The correct choice is therefore .

Example Question #3 : Period And Amplitude

Which of the given functions has the greatest amplitude?

Possible Answers:

Correct answer:

Explanation:

The amplitude of a function is the amount by which the graph of the function travels above and below its midline. When graphing a sine function, the value of the amplitude is equivalent to the value of the coefficient of the sine. Similarly, the coefficient associated with the x-value is related to the function's period. The largest coefficient associated with the sine in the provided functions is 2; therefore the correct answer is .

The amplitude is dictated by the coefficient of the trigonometric function. In this case, all of the other functions have a coefficient of one or one-half.

Example Question #1 : Graphing Piecewise And Recusive Functions

Define a function  as follows:

How many -intercept(s) does the graph of  have?

Possible Answers:

One 

Two

Four

None

Three

Correct answer:

None

Explanation:

To find the -coordinates of possible -intercepts, set each of the expressions in the definition equal to 0, making sure that the solution is on the interval on which  is so defined.

 on the interval 

 or 

However, neither value is in the interval , so neither is an -intercept.

 

 on the interval 

However, this value is not in the interval , so this is not an -intercept.

 

  on the interval 

However, this value is not in the interval , so this is not an -intercept.

 

 on the interval 

However, neither value is in the interval , so neither is an -intercept.

 

The graph of  has no -intercepts.

Example Question #11 : Graphing Functions

Define a function  as follows:

How many -intercept(s) does the graph of  have?

 

Possible Answers:

Four

One

None

Two

Three

Correct answer:

Two

Explanation:

To find the -coordinates of possible -intercepts, set each of the expressions in the definition equal to 0, making sure that the solution is on the interval on which  is so defined.

 

 on the interval 

However, this value is not in the interval , so this is not an -intercept.

 

 on the interval 

 or 

 is on the interval , so  is an -intercept. 

 

 

 on the interval 

 is on the interval , so  is an -intercept. 

 

  on the interval 

However, this value is not in the interval , so this is not an -intercept.

 

The graph has two -intercepts,  and .

Example Question #3 : Graphing Piecewise And Recusive Functions

Define function  as follows:

Give the -intercept of the graph of the function.

Possible Answers:

The graph does not have a -intercept.

Correct answer:

Explanation:

To find the -intercept, evaluate  using the definition of  on the interval that includes the value 0. Since 

on the interval  ,

evaluate:

The -intercept is .

Example Question #3 : Graphing Piecewise And Recusive Functions

Define a function  as follows:

At which of the following values of  is  discontinuous?

I) 

II) 

III) 

Possible Answers:

I and III only

All of I, II, and III

II and III only

I and II only

None of I, II, and III

Correct answer:

I and III only

Explanation:

To determine whether  is continuous at , we examine the definitions of  on both sides of , and evaluate both for :

 

 evaluated for :

 evaluated for :

Since the values do not coincide,  is discontinuous at .

 

We do the same thing with the other two boundary values 0 and .

 

 evaluated for :

 evaluated for :

Since the values coincide,  is continuous at .

 

 turns out to be undefined for , (since  is undefined), so  is discontinuous at .

 

The correct response is I and III only.

Example Question #5 : Graphing Piecewise And Recusive Functions

Define a function  as follows:

At which of the following values of  is the graph of  discontinuous?

I) 

II) 

III) 

Possible Answers:

I and III only

I and II only

None of I, II, and III

All of I, II, and III

II and III only

Correct answer:

II and III only

Explanation:

To determine whether  is continuous at , we examine the definitions of  on both sides of , and evaluate both for :

 

 evaluated for :

 evaluated for :

Since the values coincide, the graph of   is continuous at .

 

We do the same thing with the other two boundary values 0 and 1:

 

 evaluated for :

 evaluated for :

Since the values do not coincide, the graph of  is discontinuous at .

 

 evaluated for :

 evaluate for :

Since the values do not coincide, the graph of  is discontinuous at .

 

II and III only is the correct response.

 

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