Linear Algebra : Operations and Properties

Study concepts, example questions & explanations for Linear Algebra

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Example Questions

Example Question #207 : Linear Algebra

Give the trace of .

Possible Answers:

Correct answer:

Explanation:

The trace of a matrix is the sum of the elements along its main diagonal, which are shown below:

.

Example Question #208 : Linear Algebra

Give the trace of .

Possible Answers:

Correct answer:

Explanation:

The trace of a matrix is the sum of the elements along its main diagonal, which are shown below:

.

Example Question #131 : Operations And Properties

Find the trace of the matrix .

Possible Answers:

None of the other answers

Correct answer:

Explanation:

To find the trace of a matrix, we simply add up the entries along the main diagonal (Start with the top-left and work your way down to the bottom right). So the trace of this matrix is .

Example Question #132 : Operations And Properties

Which of the following  matrices is guaranteed NOT to have a trace of ?

Possible Answers:

Any skew-symmetric matrix

A linear transformation (mapping) matrix

The identity matrix

The zero matrix

Any symmetric matrix 

Correct answer:

The identity matrix

Explanation:

The identity matrix of any size has  along its main diagonal, and thus cannot have a trace of .

Example Question #1 : Norms

Find the norm of the following vector.

 

Possible Answers:

Correct answer:

Explanation:

The norm of a vector is simply the square root of the sum of each component squared. 

Example Question #1 : Norms

Find the norm of vector .

Possible Answers:

Correct answer:

Explanation:

In order to find the norm, we need to square each component, sum them up, and then take the square root.

Example Question #1 : Norms

Find the norm, , given 

Possible Answers:

Correct answer:

Explanation:

By definition, 

,

therefore,

.

Example Question #1 : Norms

Calculate the norm of  , or , given

,

 .

 

Possible Answers:

Can not be determined.

Correct answer:

Explanation:

First, we need to find .  This is, by definition,

.

Therefore, 

.

Example Question #2 : Norms

Find the norm of the vector

Possible Answers:

Correct answer:

Explanation:

To find the norm, square each component, add, then take the square root:

Example Question #1 : Norms

Find a unit vector in the same direction as

Possible Answers:

Correct answer:

Explanation:

First, find the length of the vector:

Because this vector has the length of 4 and a unit vector would have a length of 1, divide everything by 4:

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