SAT II Math I : SAT Subject Test in Math I

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

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Example Questions

Example Question #11 : Real And Complex Numbers

Which of the following choices gives a sixth root of sixty-four?

Possible Answers:

All of these

Correct answer:

All of these

Explanation:

Let  be a sixth root of 64. The question is to find a solution of the equation

.

Subtracting 64 from both sides, this equation becomes

64 is a perfect square (of 8) The binomial at left can be factored first as the difference of two squares:

8 is a perfect cube (of 2), so the two binomials can be factored as the sum and difference, respectively, of two cubes:

The equation therefore becomes 

.

By the Zero Product Principle, one of these factors must be equal to 0.

If , then ; if , then . Therefore,  and 2 are sixth roots of 64. However, these are not choices, so we examine the other polynomials for their zeroes.

 

If , then, setting  in the following quadratic formula:

 

If , then, setting  in the quadratic formula:

 

Therefore, the set of sixth roots of 64 is 

.

All four choices appear in this set.

Example Question #41 : Number Theory

Let  and  be complex numbers.  and  denote their complex conjugates. 

Evaluate .

Possible Answers:

None of these

Correct answer:

None of these

Explanation:

Knowing the actual values of  and   is not necessary to solve this problem. The product of the complex conjugates of two numbers is equal to the complex conjugate of the product of the numbers; that is,

 

, so , and

,

which is not among the choices.

Example Question #41 : Number Theory

 denotes the complex conjugate of .

If , then evaluate .

Possible Answers:

None of these

Correct answer:

Explanation:

Applying the Power of a Product Rule:

The complex conjugate of an imaginary number  is ; the product of the two is 

, so, setting  in the above pattern:

Consequently, 

Example Question #1 : Mathematical Relationships

Evaluate the expression.

Possible Answers:

Correct answer:

Explanation:

Follow the correct order of operations: parenthenses, exponents, multiplication, division, addition, subtraction.

First, evaluate any terms in parenthesis.

Next, evaluate the exponent.

Divide.

Finally, add.

Example Question #1 : Elementary Operations

Evalute the expression:

Possible Answers:

Correct answer:

Explanation:

Follow the correct order of operations: parentheses, exponents, multiplication, division, addition, subtraction. (This is typically abbreviated as PEMDAS. Note that both multiplication and division, and addition and subtraction, are equal to each other in terms of rank, so when both are present, solving the equation proceeds from left to right).

First, simplify anything in parentheses.

Next, simplify any terms with exponents.

Now, perform multiplication.

Since all we are left with is addition and subtraction, we perform simplification from left to right.

Thus, our answer is:

Example Question #1 : Elementary Operations

Add in modulo 7:

Possible Answers:

Correct answer:

Explanation:

In modulo 7 arithmetic, a number is congruent to the remainder of its division by 7. 

Therefore, since  and ,

,

and the correct response is 3.

Example Question #1 : Mathematical Relationships

Add:  

Possible Answers:

Correct answer:

Explanation:

To solve , make sure the digits are aligned with the correct placeholder.  It is also possible to add term by term.

The correct answer is: 

Example Question #5 : Mathematical Relationships

Evaluate: .

Possible Answers:

Correct answer:

Explanation:

Step 1: Recall PEMDAS...

Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.

Step 2: Perform the evaluation in separate pieces...

Step 3: Replace the values and keep the signs..

Step 4: Evaluate:

 

Example Question #6 : Mathematical Relationships

Find the sum of the numbers:  

Possible Answers:

Correct answer:

Explanation:

Add all the ones digits.

Add the tens digits with the two as the carryover.

Combine this value with the ones digit of the first number.

The answer is:  

Example Question #7 : Mathematical Relationships

Evaluate:  

Possible Answers:

Correct answer:

Explanation:

Add the ones digits.

Add the tens digits with the tens digit of the previous number as carryover.

Repeat the process with the hundreds digits.

Combine this number with the ones digits of the previous calculations.

The answer is:  

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