Update src/3_vector_spaces.md

src/3_vector_spaces.md

@@ -90,9 +90,9 @@ You might be already familiar with the concept of performing a number of various
 !!! info "Scalar multiplication" 
     I can multiply a vector by a scalar number (either real or complex) to produce another vector, $$\vec{c} = \lambda \vec{a}.$$ 
     Addition and scalar multiplication of vectors are both *associative* and *distributive*, so the following relations hold
-    $$1. \hspace{5pt} (\lambda \mu) \vec{a} = \lambda (\mu \vec{a}) = \mu (\lambda \vec{a})$$
-    $$2. \hspace{5pt} \lambda (\vec{a} + \vec{b}) = \lambda \vec{a} + \lambda \vec{b}$$
-    $$3. \hspace{5pt} (\lambda + \mu)\vec{a} = \lambda \vec{a} +\mu \vec{a}$$
+    $$\begin{align} &1. \qquad (\lambda \mu) \vec{a} = \lambda (\mu \vec{a}) = \mu (\lambda \vec{a})\\
+    &2. \qquad \lambda (\vec{a} + \vec{b}) = \lambda \vec{a} + \lambda \vec{b}\\
+    &3. \qquad (\lambda + \mu)\vec{a} = \lambda \vec{a} +\mu \vec{a} \end{align}$$
  
 ### Vector products