SAT II Math II : SAT Subject Test in Math II

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

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Example Questions

Example Question #4 : Matrices

Give the determinant of the matrix 

Possible Answers:

Correct answer:

Explanation:

The determinant of the matrix  is 

Substitute :

Example Question #3 : Matrices

Multiply:

Possible Answers:

Correct answer:

Explanation:

The product of a 2 x 2 matrix and a 2 x 1 matrix is a 2 x 1 matrix.

Multiply each row in the first matrix by the column matrix by multiplying elements in corresponding positions, then adding the products, as follows:

Example Question #1 : Matrices

Let .

Give .

Possible Answers:

 is not defined.

Correct answer:

 is not defined.

Explanation:

 has three rows and two columns; since the number of rows is not equal to the number of columns,  is not a square matrix, and, therefore, it does not have an inverse.

Example Question #1 : Matrices

Define matrix  .

For which of the following matrix values of  is the expression  defined?

I: 

 

II: 

 

III: 

Possible Answers:

I only

I and II only

II and II only

I and III only

I, II, and III

Correct answer:

I only

Explanation:

For the matrix sum  to be defined, it is necessary and sufficent for  and  to have the same number of rows and the same number of columns.  has three rows and two columns; of the three choices, only (I) has the same dimensions.

Example Question #7 : Matrices

Let  and  be the 2 x 2 identity matrix. 

Let .

Which of the following is equal to ?

Possible Answers:

Correct answer:

Explanation:

The 2 x 2 identity matrix is  .

 

, or, equivalently,

,

so

Subtract the elements in the corresponding positions:

Example Question #81 : Mathematical Relationships

Calculate: 

Possible Answers:

Correct answer:

Explanation:

To add two matrices, add the elements in corresponding positions:

Example Question #81 : Mathematical Relationships

Solve for :

Possible Answers:

 or 

 or 

The equation has no solution.

Correct answer:

 or 

Explanation:

The determinant of a matrix can be evaluated as follows:

Therefore, the equation can be rewritten:

The solution set is

 or .

Example Question #11 : Matrices

Multiply:

Possible Answers:

The matrices cannot be multiplied.

Correct answer:

The matrices cannot be multiplied.

Explanation:

Two matrices can be multiplied if and only if the number of columns in the first matrix and the number of rows in the second are equal. The first matrix has two columns; the second matrix has one row. This violates the condition, so they cannot be multiplied in this order.

Example Question #92 : Mathematical Relationships

Evaluate:

Possible Answers:

Correct answer:

Explanation:

The determinant of the matrix  is 

Substitute :

Example Question #12 : Matrices

Define .

Give .

Possible Answers:

 is not defined.

Correct answer:

Explanation:

The inverse of a 2 x 2 matrix  , if it exists, is the matrix 

.

First, we need to establish that the inverse is defined, which it is if and only if the determinant .

Set , and check:

The inverse exists.

The process: First, switch the upper-left and lower-right entries, and change the other two entries to their opposites:

Then divide the new matrix elementwise by the determinant of the original matrix, which is .

The inverse is

 

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