Originated from ln (1-x 2-y 2)

1-x^2-y^2≥0

x^2+y^2≤ 1

The domain of function z is a circle with the origin as the center and the radius of 1.

Extended data:

Finding the domain of function mainly includes three kinds of problems: abstract function, general function and function application. Meaning refers to the value range of independent variable X.

Definition domain, corresponding rules and value domain are the three basic "components" of function construction. There is no doubt that the principle of "domain priority" is implemented in mathematics at ordinary times.

In fact, the positions of domain and value domain are quite consistent, so we must not favor one over the other, not to mention that they are transforming each other at any time (a typical example is the transformation between domain and value domain).

If the range of a function is infinite, it is not always easy to find the range of this function. It is sometimes invalid to rely on the operational nature of inequality, and the function value must be considered in combination with the parity, monotonicity, boundedness and periodicity of the function.