From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Mon, 11 Feb 2019 11:04:39 +0000 (+1100)
Subject: add index rule for i^n in C
X-Git-Tag: yr12~254^2~6
X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/2f7e9eaa7f0794d4e55e501b085de4d67434b497

add index rule for i^n in C
---

diff --git a/spec/complex.md b/spec/complex.md
index d0b6625..5809170 100755
--- a/spec/complex.md
+++ b/spec/complex.md
@@ -53,6 +53,8 @@ Therefore..
 - $i^{4n+2} = -1$
 - $i^{4n+3} = -i$
 
+Divide by 4 and take remainder
+
 ### Multiplying complex expressions
 
 If $z_1 = a+bi$ and $z_2=c+di$, then
@@ -97,7 +99,7 @@ ${z_1 \over z_2} = {{(a+bi)(c-di)} \over {c^2+d^2}}$
 To solve $z^2+a^2=0$ (sum of two squares):
 
 $z^2+a^2=z^2-(ai)^2$
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$=(z+ai)(z-ai)$ 
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$=(z+ai)(z-ai)$
 
 ## Polar form