SAT Math : Algebraic Functions

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #81 : How To Find F(X)

Function 4

Define  to be the function graphed above.

Give the -intercept of the graph of the function , which is defined as 

Possible Answers:

The graph of  has no -intercept.

Correct answer:

Explanation:

The -intercept of a function is the point at which , so we can find this by evaluating .

As can be seen in the diagram below, .

Function 4a

The -intercept is .

Example Question #91 : How To Find F(X)

Two functions

Define  and  to be the functions graphed above. Evaluate 

.

Possible Answers:

The expression is not defined.

Correct answer:

The expression is not defined.

Explanation:

It can be seen below that a horizontal line can be drawn through two points of the graph of .

Hlt

 fails the Horizontal Line Test, which means that  has no inverse.  does not exist, so the expression  is undefined.

Example Question #92 : How To Find F(X)

Function 4

Define  as the function graphed above. Define function .

Evaluate .

Possible Answers:

3 is not in the domain of .

Correct answer:

Explanation:

.

As can be seen in the diagram below, .Function 4a

Therefore, 

, so

Example Question #93 : How To Find F(X)

Two functions

Define  and  to be the functions graphed above.

Evaluate 

Possible Answers:

4 is not in the domain of .

Correct answer:

Explanation:

.

From the diagram below, it can be seen that 

Two functions g 1

Therefore, .

From the diagram below, it can be seen that 

.

Two functions f

Therefore, the correct response is that .

Example Question #94 : How To Find F(X)

Two functions

Define  and  to be the functions graphed above. Evaluate 

Possible Answers:

 is undefined.

Correct answer:

Explanation:

.

From the diagram below, it can be seen that 

Two functions g 1

Therefore, .

From the diagram below, it can be seen that 

Two functions f

so, by definition,

.

Therefore, the correct response is that

.

Example Question #95 : How To Find F(X)

Function 4

Define  as the function graphed above. Define function .

Evaluate .

Possible Answers:

4 is outside the domain of 

Correct answer:

Explanation:

, so 

From the diagram below, we see that .

Function 4a

The correct response is that .

Example Question #96 : How To Find F(X)

Two functions

Define  and  to be the functions graphed above. For which of the following values of  is the statement 

a true statement?

Possible Answers:

The statement is not correct for any value of .

Correct answer:

Explanation:

or

This can be solved by graphing  and  on the same set of axes and noting their points of intersection:

Two functions together

The graphs of the two functions intersect at the point . Therefore, 

, and 

.

The correct response is .

Example Question #97 : How To Find F(X)

Function 4

Define  to be the function graphed above.

Which of the following is an -intercept of the graph of the function , if  is defined as

 ?

Possible Answers:

The graph of  has no -intercept.

Correct answer:

Explanation:

An -intercept of the graph of  has as its -coordinate a value such that

,

or, equivalently,

From the diagram, we can see that

Therefore, to find the -intercepts of , set  equal to these numbers; equivalently, subtract 5 from each number. We get that

Therefore, the -intercepts of the graph of  are the points

.

The correct choice is .

Example Question #131 : Algebraic Functions

Function 4

Define  to be the function graphed above.

Give the -intercept of the graph of the function , which is defined as 

.

Possible Answers:

The graph of  has no -intercept.

Correct answer:

Explanation:

The -intercept of a function is the point at which , so we can find this by evaluating .

As can be seen in the diagram below, .

Function 4a

Therefore, , and the correct response is .

Example Question #99 : How To Find F(X)

Define a function  as follows:

, where the domain of  is the set .

Give the range of .

Possible Answers:

Correct answer:

Explanation:

This problem can be solved by examining the behavior of the graph of , which is a parabola.

Since the quadratic coefficient is 1, a positive number, its vertex is a minumum. The -coordinate of the vertex can be found by setting , and calculating:

The -coordinate is

The minimum value of  is therefore 1, and this occurs at . This makes 1 the lower bound of the range.

Since the graph of  is a parabola, it decreases everywhere for  and increases everywhere for . Therefore, we can evaluate  and , and choose the higher value as the maximum value on the given domain.

We choose 26 as the upper bound of the range.

Therefore, the range of , given the domain restriction, is the set .

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