From Förberedande kurs i matematik 2

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-	{{NAVCONTENT_START}}	+	Complex numbers satisfy the same rules of arithmetic as ordinary numbers, with the addition that <math>i^2=-1</math>. The distributivity rule gives that
-	<center> [[Image:3_1_1c.gif]] </center>	+
-	{{NAVCONTENT_STOP}}	+	{{Displayed math||<math>\begin{align}
		+	i(2+3i)
		+	&= i\cdot 2 + i\cdot 3i\\[5pt]
		+	&= 2i+3i^2\\[5pt]
		+	&= 2i+3\cdot (-1)\\[5pt]
		+	&= 2i-3\\[5pt]
		+	&= -3+2i\,\textrm{.}
		+	\end{align}</math>}}

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Current revision

Complex numbers satisfy the same rules of arithmetic as ordinary numbers, with the addition that \displaystyle i^2=-1. The distributivity rule gives that

\displaystyle \begin{align} i(2+3i) &= i\cdot 2 + i\cdot 3i\\[5pt] &= 2i+3i^2\\[5pt] &= 2i+3\cdot (-1)\\[5pt] &= 2i-3\\[5pt] &= -3+2i\,\textrm{.} \end{align}