\begin{definition}[Definition:Complex Number/Imaginary Part]
Let $z = a + i b$ be a complex number.
The '''imaginary part''' of $z$ is the coefficient $b$ ('''note:''' not $i b$).
The '''imaginary part''' of a complex number $z$ is usually denoted on {{ProofWiki}} by $\map \Im z$ or $\Im z$.
\end{definition}