What two functions do not have a domain of all real numbers?

Two functions that do not have a domain of all real numbers are the square root function, ( f(x) = \sqrt{x} ), which is only defined for ( x \geq 0 ), and the logarithmic function, ( g(x) = \ln(x) ), which is only defined for ( x > 0 ). Both functions have restrictions that prevent them from taking all real numbers as inputs.