How to write Latex imaginary part symbol of a complex number? The real number b is called the imaginary part of the complex number a + ib.

Let $a,b\in \mathbb{R}$ and $z=a+ib \in \mathbb{C}$.

Real part and imaginary part are defined like follows:

\[\begin{array}{ccc} a & + & i & b\\ \uparrow & & &\uparrow \\ \Re (z) & & &\Im (z) \\ \text { Real part } & && \text { Imaginary part } \end{array}\]

Default Latex imaginary part symbol

You can use \Im function:

$$\Im (z)= \Im(a+ib)=b$$
\[\Im (z)= \Im(a+ib)=b\]

Latex imaginary part symbol using amsmath and operatorname

You can use \operatorname function:

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}

$$\operatorname{Im}(z)= \operatorname{Im}(a+ib)=b$$

\end{document}
\[\operatorname{Im}(z)= \operatorname{Im}(a+ib)=b\]

Latex imaginary part symbol using amsfonts and mathfrak

You can use \mathfrak function:

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsfonts}
\begin{document}

$$\mathfrak{Im}(z)= \mathfrak{Im}(a+ib)=b$$

\end{document}
\[\mathfrak{Im}(z)= \mathfrak{Im}(a+ib)=b\]

How to write Latex real part symbol

How to write Latex real part symbol