AnalystForum uses MathJax for making user-friendly math formulas. Here are some examples of common formulas to help you get started:
Present Value of a Future Cash Flow
$$
PV = {FV \over (1 + r)^N}
$$
PV = {FV \over (1 + r)^N}
Sharpe Ratio
$$
Sharpe = {R_p - R_f \over \sigma_p}
$$
Sharpe = {R_p - R_f \over \sigma_p}
Standard Deviation
$$
\sigma = \sqrt{ \frac{1}{N} \sum_{i=1}^N (x_i -\mu)^2}
$$
\sigma = \sqrt{ \frac{1}{N} \sum_{i=1}^N (x_i -\mu)^2}
Please visit this MathJax Basic Tutorial and Quick Reference for more examples.