Final answer:
The function y = 2x / √(x² + 1) has a horizontal asymptote at y = 2, as x approaches infinity or negative infinity. Hence, the correct answer is A. y = 2.
Step-by-step explanation:
To find the horizontal asymptotes of the function y = 2x / √(x² + 1), we need to determine the behavior of the function as x approaches infinity or negative infinity.
As x goes to infinity or negative infinity, the x² term dominates in the denominator, and the square root of x² behaves like x. Therefore, the function simplifies to:
y = 2x / x
Which further simplifies to:
y = 2
Thus, the function has a horizontal asymptote at y = 2.
The correct answer is A. y = 2.