Trying paste of an image again like this image:

Using the button , I would like to preview $E = \gamma m c^2$ where $\gamma = \frac{1}{\sqrt{1-\beta^2}}$ and $\beta = \frac{v}{c}$.

But there is a problem with the superscript (upper limit) in sum functions... $\sum_{n=1}^{\infty} 2^{-n} = 1$