Function with exactly two parameters of the form z = f(x, y).
function's domain for x
function's domain for y
Returns the value z = f(x, y). If x is not in domainX or y is not in domainY an error is returned.
Returns the value z = f(x, y). If x is not in domainX or y is not in domainY an error is returned. However, a fuzziness is allowed with a certain tolerance.