Comma as separator for x and y coordinate, better to use |

[echteinfachtv]

If you enter for instance: -x^2-2x+8
you get a parabel that holds a -1,9 on top (apex).

Actually it would be better to have a (-1|9) there to make it clear that it is not a value of -1.9 (remember, many countries use a comma instead dot for decimal).

How can I change this in the current code? In what line do I find the output?
Thanks, Kai