How to use mathematical language in your posts

Use $ to start and end any mathematical part to your post. 

Whithin the dollar signs the following can be used:

"^" will give "to the power of"

"_" will give a subscript

"\frac{1}{2}" will display $\frac{1}{2}$

"\sum" will display a sigma sign

For example 

"\sum_{r=1}^{10} \frac{d^r y}{dx^r} = x^2" will display 

$\sum_{r=1}^{10} \frac{d^r y}{dx^r} = x^2$