When entering functions, you'll need to use javascript notation.
Specifically, you will need to use ** for exponentiation. Use x**2, not x^2.
You will also need to use * for multiplication. Javascript does not automatically interpret parentheses or juxtaposition as multiplication. Use 2*(x**2) or 2*x**2, not 2x**2 or 2(x**2).
If your function doesn't appear to work, you may want to try adding parentheses. Use -(x**2), not -x**2.
Using variables used in the code of this webpage may give bad results.
Please avoid entering arbitrary javascript code as this will execute it many times.
Play around with the examples below to get a sense of how to input functions.