Final answer:
The domain of the function f(x) = x^2 + 1 is all real numbers, because any real number can be squared and then have 1 added to it without restrictions.
Step-by-step explanation:
The domain of the function f(x) = x^2 + 1 is all real numbers. This is because the equation involves squaring the variable x, which is defined for all real values of x since squaring any real number will yield a real number. Additionally, adding 1 to a real number still results in a real number, which means there are no restrictions on the value of x in this function.
The domain is not limited to only non-negative, positive, or all real numbers except for 0, as a real square function can accept any real number regardless of its sign.