College Algebra CLEP Prep Practice Exam

What is the domain of the function y = x2 + 1?

1. x ≥ 1

2. x > 1

3. x ≥ 0

4. x > 0

The correct answer is: x ≥ 0

The function y = x^2 + 1 is a quadratic function which is defined for all real numbers. This means that any value within the real number system, including negative numbers, can be plugged in for x and give a valid output. Therefore, the domain of this function is all real numbers, or x ≥ 0. Option A, x ≥ 1, is incorrect because it restricts the domain to only values greater than or equal to 1. Since the function is defined for all real numbers, this domain is too limited. Option B, x > 1, is also incorrect for the same reason as option A. Restricting the domain to only values greater than 1 would exclude valid inputs such as 0 or -1. Option D, x > 0, is incorrect because it still excludes the possibility of 0 being input into the function. Overall