Complex Numbers
| Example | Meaning and verbal equivalent | Remarks |
|---|---|---|
| i j | imaginary unit; i² = −1 | In electrotechnology, j is generally used. |
| Re z | real part of z | z = x + iy, where x = Re z and y = Im z |
| Im z | imaginary part of z | |
| ∣z∣ | absolute value of z; modulus of z | mod z is also used |
| arg z | argument of z; phase of z | z = reiφ, where r = ∣z∣ and φ = arg z, i.e. Re z = r cos φ and Im z = r sin φ |
| z* | (complex) conjugate of z | sometimes a bar above z is used instead of z* |
| sgn z | signum z | sgn z = z / ∣z∣ = exp(i arg z) for z ≠ 0, sgn 0 = 0 |
Read more about this topic: ISO 31-11
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