Complex Analysis : Complex Analysis

Study concepts, example questions & explanations for Complex Analysis

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Example Questions

Example Question #11 : Complex Analysis

Evaluate:

Possible Answers:

Correct answer:

Explanation:

The general formula to figure out the modulus is

We apply this to get

Example Question #11 : Complex Analysis

Evaluate:

Possible Answers:

Correct answer:

Explanation:

The general formula to figure out the modulus is

.

We apply this notion to get.

Example Question #12 : Complex Analysis

Evaluate 

Possible Answers:

None of the other answers

64

-64

-64i

64i

Correct answer:

-64

Explanation:

Converting from rectangular to polar coordinates gives us

So 

Example Question #13 : Complex Analysis

Compute 

Possible Answers:

Correct answer:

Explanation:

Converting from Rectangular to Polar Coordinates

 

Evaluating for 

we get that 

Example Question #14 : Complex Analysis

The 5th roots of unity are the five unique solutions to which equation?

Possible Answers:

None of these

Correct answer:

Explanation:

A 5th root of unity is a complex number  such that . Manipulating this equation yields .

Example Question #16 : Complex Analysis

What is the magnitude of the following complex number?

Possible Answers:

None of these

Correct answer:

Explanation:

The magnitude of a complex number  is defined as

So the modulus of  is

.

Example Question #17 : Complex Analysis

What is the magnitude of the following complex number?

Possible Answers:

None of these

Correct answer:

Explanation:

The magnitude of a complex number  is defined as

So the modulus of  is

.

Example Question #18 : Complex Analysis

What is the magnitude of the following complex number?

Possible Answers:

None of these

Correct answer:

Explanation:

The magnitude of a complex number  is defined as

Because the complex number  has no imaginary part, we can write it in the form . Then the modulus of  is

.

Example Question #19 : Complex Analysis

What is the argument of the following complex number?

Possible Answers:

None of these

Correct answer:

Explanation:

Note that the complex number  lies in the first quadrant of the complex plane.

 

For a complex number , the argument of  is defined as the real number  such that

,

where  is in radians.

 

Then the argument of  is

.

 

The angle  lies in the third quadrant of the complex plane, but the angle  lies in the first quadrant, as does . So .

Example Question #20 : Complex Analysis

What is the argument of the following complex number in radians, rounded to the nearest hundredth?

Possible Answers:

None of these

Correct answer:

Explanation:

Note that the complex number  lies in the fourth quadrant of the complex plane.

 

For a complex number , the argument of  is defined as the real number  such that

,

where  is in radians.

 

Then the argument of  is

.

 

The angle  lies in the second quadrant of the complex plane, but the angle  lies in the fourth quadrant, as does . So .

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