中等MATH-FUNC-009
What is the range of f(x) = x^2 + 1 for real x?
A. All real numbers
B. y ≥ 0
C. y ≥ 1✓ 答案
D. y ≤ 1
解說
x^2 is at least 0, so x^2 + 1 is at least 1. The range is y ≥ 1. The set y ≥ 0 would be the range of x^2 itself.
x^2 is at least 0, so x^2 + 1 is at least 1. The range is y ≥ 1. The set y ≥ 0 would be the range of x^2 itself.