[texhax] Adjusting parentheses for intervals and functions

[Plamen Tanovski]

Hi,

should the size of the parentheses/brackets for intervals/functions be
adjusted? 

Like: 

the interval $(\frac{x}{5}, \frac{x}{3})$,
the function $f(x^{\frac{\pi}{2}})$

or

the interval $\left(\frac{x}{5}, \frac{x}{3}\right)$,
the function $f\left(x^{\frac{\pi}{2}}\right)$


Is there any book on math typography, which discusses that?

Best regards,
P.