human2php math function parser

π is "pi"; when it fails, use pow($a, $b), not $a^$b


f(x): 

   x_start:  (optional x_end:  count: )

see also number guesser, which is used to display nice numbers

well parsing f(x):
sin(x);
sin(2*x);
x^3+1;
cos(x^2)+x^2;