What is the range of the function f(x) = 2 + sqrt(4 - x^2)?
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Correct answer
A. [2, 4]
Principle or equation
The range of a function is the set of all possible output values. For f(x) = 2 + sqrt(4 - x^2), the square root term ranges from 0 to 2, so f(x) ranges from 2 to 4.
Why this answer is correct
Since 4 - x^2 ≥ 0, we have -2 ≤ x ≤ 2. The minimum of sqrt(4 - x^2) is 0 (at x = ±2), and the maximum is 2 (at x = 0). Therefore, f(x) = 2 + sqrt(4 - x^2) has minimum 2 and maximum 4, so the range is [2, 4].
Example
For f(x) = 1 + sqrt(9 - x^2), the range is [1, 4] because sqrt(9 - x^2) ranges from 0 to 3.
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