Final answer:
The domain of the function g(u) = 1/(1+1/u) is all real numbers except zero because division by zero is undefined in mathematics.
Step-by-step explanation:
The domain of a function is set of all possible inputs, or the 'x' values, for which the function is defined. In the case of the function g(u) = 1/(1+1/u), we can see that there is a division by 'u' in the function. A function in which there is division by a variable is not defined when the variable is equal to zero.
Therefore, the value 'u' cannot be zero in this function. So, the domain of this function is all real numbers except 0.
Learn more about Domain of a Function