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 : Other Properties

Define the functions  and  on the set of real numbers as follows:

Give the natural domain of the composite function .

Possible Answers:

Correct answer:

Explanation:

The natural domain of the composite function  is defined to be the intersection of the two sets.

 

One set is the natural domain of . Since  is defined to be the square root of an expression, the radicand must be nonnegative. Therefore,

This set is .

 

The other set is the set of numbers that the function  pairs with a number within the domain of . Since the radicand of the square root in  must be nonnegative, 

For  to fall within this set:

This set is .

 

, which is the natural domain.

Example Question #1 : Solving Linear Functions

If , what must  be?

Possible Answers:

Correct answer:

Explanation:

Replace the value of negative two with the x-variable.

There is no need to use the FOIL method to expand the binomial.

The answer is:  

Example Question #2 : Solving Linear Functions

Let .  What is the value of ?

Possible Answers:

Correct answer:

Explanation:

Substitute the fraction as .

Multiply the whole number with the numerator.

Convert the expression so that both terms have similar denominators.

The answer is:  

Example Question #1 : Solving Linear Functions

If , what must  be?

Possible Answers:

Correct answer:

Explanation:

A function of x equals five.  This can be translated to:

This means that every point on the x-axis has a y value of five.  

Therefore, .

The answer is:  

Example Question #1 : Solving Exponential, Logarithmic, And Radical Functions

Rewrite as a single logarithmic expression:

Possible Answers:

Correct answer:

Explanation:

Using the properties of logarithms

 and ,

simplify as follows:

Example Question #2 : Solving Exponential, Logarithmic, And Radical Functions

Simplify by rationalizing the denominator:

Possible Answers:

Correct answer:

Explanation:

Multiply the numerator and the denominator by the conjugate of the denominator, which is . Then take advantage of the distributive properties and the difference of squares pattern:

 

Example Question #1 : Solving Exponential, Logarithmic, And Radical Functions

Simplify:

You may assume that  is a nonnegative real number.

Possible Answers:

Correct answer:

Explanation:

The best way to simplify a radical within a radical is to rewrite each root as a fractional exponent, then convert back.

First, rewrite the roots as exponents.

Then convert back to a radical and rationalizing the denominator:

Example Question #1 : Solving Functions

Let .   What is the value of ?

Possible Answers:

Correct answer:

Explanation:

Replace the integer as .

Evaluate each negative exponent.

Sum the fractions.

The answer is:  

Example Question #4 : Solving Functions

Find :   

Possible Answers:

Correct answer:

Explanation:

Square both sides to eliminate the radical.

Add five on both sides.

Divide by negative three on both sides.

The answer is:  

Example Question #5 : Solving Functions

If , what is the value of ?

Possible Answers:

 

Correct answer:

 

Explanation:

Substitute the value of negative three as .

The terms will be imaginary.  We can factor out an  out of the right side.  Replace them with .

The answer is:  

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