What is the use of modulus in complex number?
The modulus of the complex number $z = a + bi$ is denoted by $|z|$ and is given by $|z| = \sqrt{a^2+b^2}$.
What is the meaning of this? What is a modulus?
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$\begingroup$A complexe number $z=a+ib$ is a point $ M$ in the plane $\Bbb R^2$. the coordinates of the point $ M $ are $(a,b)$.
the modulus of $ z$ represents the Euclidian distance between the point $M(a,b)$ and the origin $O(0,0)$.
$$d(O,M)=||\vec{OM}||=\sqrt{(a-0)^2+(b-0)^2}$$$$=\sqrt{a^2+b^2}=|z|$$
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