To create cheat sheet first you need to select formulas which you want to include in it. To select formula click at picture next to formula.
You can choose formulas from different pages.
After you have selected all the formulas which you would like to include in cheat sheet, click the "Generate PDF" button.

$$ a^p = \underbrace{a \cdot a \cdot \dots a }_p ~~~( \text{if} ~~ p \in \mathbb{N} ) $$ 

$$ a^0 = 1 ~~~ (\text{if} ~~~ a \ne 0) $$ 

$$ a^r \cdot a^s = a^{r+s} $$ 

$$ \frac{a^r}{a^s} = a^{rs} $$ 

$$ \left( a^r\right)^s = a^{r \cdot s} $$ 

$$ (a \cdot b)^r = a^r \cdot b^r $$ 

$$ \left( \frac{a}{b} \right)^r = \frac{a^r}{b^r} $$ 

$$ a^{r} = \frac{1}{a^r} $$ 

$$ a^{\Large\frac{r}{s}} = \sqrt[\Large{s}]{a^r} $$ 
Please tell me how can I make this better.