[spec] EOL formatting for complex.md

diff --git a/spec/complex.md b/spec/complex.md
index b70737f4fccbcf3ae252a7b687272536516f1339..91066042af574e64cee549401a65d09c097449a3 100755 (executable)
--- a/spec/complex.md
+++ b/spec/complex.md
@@ -96,12 +96,11 @@ $$|{z}|=\sqrt{a^2+b^2} \quad  \therefore z \overline{z} = |z|^2$$
 
 ### Dividing complex numbers
 
-$${{z_1} \over {z_2}} = {{z_1\ {z_2}^{-1}}} = {{z_1 \overline{z_2}} \over {{|z_2|}^2}} \quad \text{multiplicative inverse}$$
-
-(using multiplicative inverse)
+$${{z_1} \over {z_2}} = {{z_1\ {z_2}^{-1}}} = {{z_1 \overline{z_2}} \over {{|z_2|}^2}} \quad \text{(multiplicative inverse)}$$
 
 In practice, rationalise denominator:
-${z_1 \over z_2} = {{(a+bi)(c-di)} \over {c^2+d^2}}$
+
+$${z_1 \over z_2} = {{(a+bi)(c-di)} \over {c^2+d^2}}$$
 
 ## Argand planes
 
@@ -129,6 +128,12 @@ $$P(z) = D(z)Q(z) + R(z)$$
 
 Let $\alpha \in \mathbb{C}$. Remainder of $P(z) \div (z - \alpha)$ is $P(\alpha)$
 
+#### Factor theorem
+If $a+bi$ is a solution to $P(z)=0$, then:
+
+- $P(a+bi)=0$
+- $z-(a+bi)$ is a factor of $P(z)$
+
 ## Conjugate root theorem
 
 If $a+bi$ is a solution to $P(z)=0$, with $a, b \in \mathbb{R}$, then the conjugate $\overline{z}=a-bi$ is also a solution.
@@ -141,7 +146,7 @@ If $a+bi$ is a solution to $P(z)=0$, with $a, b \in \mathbb{R}$, then the conjug
 - $\theta=\operatorname{arg}(z)$ (on CAS: `arg(a+bi)`)
 - **principal argument** is $\operatorname{Arg}(z) \in (-\pi, \pi]$ (note capital $\operatorname{Arg}$)
 
-Note each complex number has multiple polar representations:
+Note each complex number has multiple polar representations:  
 $z=r \operatorname{cis} \theta = r \operatorname{cis} (\theta+2 n\pi$) where $n$ is integer number of revolutions
 
 ### Conjugate in polar form