$\displaystyle \frac{1}{x}$\displaystyle \frac{1}{x}

$\displaystyle \frac{1-x}{2x}$\displaystyle \frac{1-x}{2x}

$\displaystyle \frac{1-2x^2}{2x}$\displaystyle \frac{1-2x^2}{2x}

$\displaystyle - \frac{1}{2x}$\displaystyle - \frac{1}{2x}