To determine which graph could represent a square root function, we need to understand the characteristics of a square root function, which can generally be represented in the form \( f(x) = \sqrt{x} \).
Key characteristics of a square root function:
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Domain: The function is defined for \( x \geq 0 \). Hence, the graph will only exist in the first quadrant and along the x-axis for non-negative values of x.
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Range: The outputs (y-values) are also non-negative, so y will be \( y \geq 0 \).
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Shape: The graph starts at the origin (0,0) and increases at a decreasing rate, curving upwards gradually.
Now, reviewing the provided descriptions:
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First graph: A straight line in the first and third quadrants. This cannot be a square root function because it does not exhibit the characteristic shape and includes negative x values.
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Second graph: A concave up parabola in the first and second quadrants. This is not a square root function since parabolas are quadratic, not square root functions.
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Third graph: An S-shaped curve. This sounds more like it could represent a polynomial or sine/cosine function but doesn’t specifically indicate properties of a square root function.
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Fourth graph: A curve in the first quadrant that passes through 3 marked points. If it starts from the origin and curves upward while remaining in the first quadrant, it has the potential to be the graph of a square root function.
Based on the characteristics of square root functions, the fourth graph is the most likely to represent a square root function.