Finding length of a complex number

In summary, the conversation discusses a complex number with a hat indicating its complexity. The length of this number is given by a formula involving the absolute values of the number and another complex number. Care must be taken when calculating the absolute value of the number in terms of its real and imaginary parts.
  • #1
Niles
1,866
0

Homework Statement


Hi all.

Please take a look at this complex number:

[tex]
\widehat C = \frac{1-\widehat a}{1+\widehat a}\widehat B,
[/tex]

where a hat indicates that the number is complex. Can you confirm me in that the length (modulus) of this complex number [itex]|\widehat C|[/itex] is given by:

[tex]
|\widehat C| = \frac{|1-\widehat a|}{|1+\widehat a|}|\widehat B|
[/tex]

Thanks in advance.Niles.
 
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  • #2
Niles said:

Homework Statement


Hi all.

Please take a look at this complex number:

[tex]
\widehat C = \frac{1-\widehat a}{1+\widehat a}\widehat B,
[/tex]

where a hat indicates that the number is complex. Can you confirm me in that the length (modulus) of this complex number [itex]|\widehat C|[/itex] is given by:

[tex]
|\widehat C| = \frac{|1-\widehat a|}{|1+\widehat a|}|\widehat B|
[/tex]

Thanks in advance.Niles.
Yes, but you need to be careful. Note that if [itex]\widehat{a} = \alpha + i\beta[/itex] then

[tex]\left|1-\widehat{a}\right| = \sqrt{\left(1-\alpha\right)^2 + \beta^2}[/tex]
 
  • #3
Thanks a lot for responding quickly.
 

1. How do you find the length of a complex number?

The length of a complex number is also known as its absolute value or modulus. To find the length, you can use the Pythagorean theorem, which states that the length of a complex number is equal to the square root of the sum of the squares of its real and imaginary parts. In formula form, this is written as |z| = √(x² + y²), where z is the complex number z = x + yi.

2. Can the length of a complex number be negative?

No, the length of a complex number cannot be negative. The length is always a positive value, as it represents the distance of the complex number from the origin on the complex plane.

3. How do you represent the length of a complex number graphically?

The length of a complex number can be represented graphically as the distance from the origin to the point on the complex plane that corresponds to the complex number. This distance is also known as the radius or magnitude of the complex number.

4. What is the relationship between the length of a complex number and its conjugate?

The length of a complex number and its conjugate are equal. This is because the conjugate of a complex number has the same real part, but an opposite imaginary part. Therefore, when using the formula to find the length of a complex number, the squared imaginary parts will cancel out, resulting in the same length for both the complex number and its conjugate.

5. How can finding the length of a complex number be useful in mathematics?

The length of a complex number can be useful in a variety of mathematical applications, such as solving equations involving complex numbers, finding roots of polynomials, and analyzing the behavior of systems with complex components. It is also an important concept in understanding the geometric properties of complex numbers on the complex plane.

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