How Do You Calculate the Magnitude and Argument of a Complex Number?

In summary, to calculate the magnitude of z= i/(6i-3), you first need to rationalize the denominator by multiplying both the numerator and denominator by the complex conjugate of the denominator, which is -i/(6i+3). This will result in z= (6-3i)/(45). Then, to find the magnitude, you take the square root of the sum of the squares of the real and imaginary parts, which will give you a magnitude of approximately 0.15. To find the argument of the real and imaginary parts, you can use the trigonometric identities of a complex number, which will give you an argument of approximately 0.321 radians for the real part and -0.321
  • #1
Benzoate
422
0

Homework Statement




calculate the magnitude of z= i/(6i-3) and the argument of the real and imaginary parts

Homework Equations





The Attempt at a Solution



z=i/6i-3

z*=i/-3+6i?

mag(z)=zz*

not sure if z* is correct.
 
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  • #2
In that kind of problem, you want to get the imaginary numbers out of the denominator. What can you multiply both the top and bottom by, to get rid of the complex denominator?
 
  • #3
berkeman said:
In that kind of problem, you want to get the imaginary numbers out of the denominator. What can you multiply both the top and bottom by, to get rid of the co8mplex denominator?

zz*=i/6i-3*(-3+6i/-3+6i)=6-3i/(45)=
sqrt((6/45)^2+(3/45)^2)=.15=mag(z)

how would I fine arg(z),Re(z),and Im(z)?
 
  • #4
Benzoate said:
zz*=i/6i-3*(-3+6i/-3+6i)=6-3i/(45)=
sqrt((6/45)^2+(3/45)^2)=.15=mag(z)

how would I fine arg(z),Re(z),and Im(z)?

Don't try to do ZZ* first. Show us how you rationalize the denominator first, okay?
 
  • #5
The complex conjugate of i/(6i- 3) is -i/(-6i-3)= i/(6i+3). You need the negative on both "i"s.

But as Berkman said, it is better to get z in the form a+ bi first by rationalizing the denominator.
 

FAQ: How Do You Calculate the Magnitude and Argument of a Complex Number?

What is the magnitude of a complex number?

The magnitude of a complex number is the distance from the origin (0,0) on the complex plane to the point representing the complex number. It is also known as the absolute value or modulus of the complex number.

How is the magnitude of a complex number calculated?

The magnitude of a complex number is calculated using the Pythagorean theorem. It is the square root of the sum of the squares of the real and imaginary parts of the complex number. Mathematically, it can be written as: |a + bi| = √(a² + b²).

Can the magnitude of a complex number be negative?

No, the magnitude of a complex number is always a positive value. It represents the distance from the origin, and distance cannot be negative.

What is the significance of the magnitude of a complex number?

The magnitude of a complex number is important in understanding the properties of the number. It can be used to calculate the phase angle, conjugate, and inverse of the complex number. It also helps in plotting the number on the complex plane and understanding its relationship with other complex numbers.

How is the magnitude of a complex number related to its argument?

The magnitude of a complex number and its argument (phase angle) are related through trigonometric functions. The magnitude is the hypotenuse of a right triangle formed by the real and imaginary parts, while the argument is the angle formed by the hypotenuse and the real axis. They are related by the equation: |z| = √(Re(z)² + Im(z)²) and arg(z) = tan⁻¹(Im(z)/Re(z)).

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