When the function is given by an analytical formula, the basis for determining the domain is as follows according to the structural characteristics of the analytical formula:

(1) If f(x) is an algebraic expression, the domain is the real number set r;

(2) If f(x) is a fraction, the domain is a set of real numbers whose denominator is not zero;

(3) If f(x) is an odd root, the domain is r;

(4) If f(x) is an even root, the domain is a set of nonnegative real numbers;

(5) If f(x) is zero, the domain is a set of non-zero real numbers;

(6) If the above situations occur at the same time, first find out their respective domains, and then find the intersection.

The definition domain of the function obtained from the actual problem should be determined according to the actual situation.