Mathematic formulas

This is a sample formula:
$\displaystyle c = \pm\sqrt{a^2 + b^2} $
$\displaystyle \int_0^1 f(x)dx = F(x)\vert _0^1
$

And this is an inline formula: $\int_0^1 f(x)dx = F(x)\vert _0^1$ and so it goes.


$\displaystyle a$ $\textstyle =$ $\displaystyle 2(b+c)$ (1)
  $\textstyle =$ $\displaystyle 2b + 2c$ (2)