Tool for calculating the value of the modulus/magnitude of a complex number |z| (absolute value): the length of the segment between the point of origin of the complex plane and the point z
Complex Number Modulus/Magnitude - dCode
Tag(s) : Arithmetics, Geometry
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The modulus (or magnitude) is the length (absolute value) in the complex plane, qualifying the complex number $ z = a + ib $ (with $ a $ the real part and $ b $ the imaginary part), it is denoted $ |z| $ and is equal to $ |z| = \sqrt{a^2 + b^2} $.
The module can be interpreted as the distance separating the point (representing the complex number) from the origin of the reference of the complex plane.
To find the modulus of a complex number $ z = a + ib $ carry out the computation $ |z| = \sqrt {a^2 + b^2} $
Example: $ z = 1+2i $ (of abscissa 1 and of ordinate 2 on the complex plane) then the modulus equals $ |z| = \sqrt{1^2+2^2} = \sqrt{5} $
A complex number in exponential notation has the form $ re^{i \theta} $, the modulus is the value of $ r $.
Example: $ 2e^{i\pi} $ has for modulus $ 2 $
See also the page about the exponential form of the complex number.
The modulus (or magnitude) of a real number is equivalent to its absolute value.
Example: $ |-3| = 3 $
For the complex numbers $ z, z_1, z_2 $ the complex modulus has the following properties:
$$ |z_1 \cdot z_2| = |z_1| \cdot |z_2| $$
$$ \left| \frac{z_1}{z_2} \right| = \frac{|z_1|}{|z_2|} \quad z_2 \ne 0 $$
$$ |z_1+z_2| \le |z_1|+|z_2| $$
A modulus is an absolute value, therefore necessarily positive (or null):
$$ |z| \ge 0 $$
The modulus of a complex number and the modulus of its conjugate are equal:
$$ |\overline z|=|z| $$
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