While searching on net about Argand diagram or complex plane we get images of both kinds which have their $y-$axis either real axis or imaginary axis.
Given $z = x + yi$, some people write $Im(z) = y$ and other $Im(z) = yi$,
So what is the TRUTH which comply with diagram as well.
From my knowledge of mathematica I know that there is no special complex plane, Wolfram has 'programmed' to include complex number.
Thnx.
The imaginary part of the complex number $z = x+yi$ is $y$ not $yi$, and we sometimes write $\operatorname{Im}(z) = y$. Likewise, we write $\operatorname{Re}(z) = x$ for the real part of $x$
On an Argand diagram, the horizontal axis is the real part, and the vertical axis is the imaginary part and should be labelled $\operatorname{Re}(z)$ and $\operatorname{Im}(z)$ respectively, although some people choose to supress the $z$ and just use $\operatorname{Re}$ and $\operatorname{Im}$.