In my textbook, it says that because of the vertical line test, the ordered pair is not a function because of it's curved shape and because that there are two Y values for all but one X. I don't know if they are using it as an example, or if there is any exception to what they are saying. No stupid answers please. Thanks in advance.
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That description is true for a parabola which opens left or right, which is one where the y is squared, like x = y^2 - 6.
But a parabola which opens up or down, where the x is squared and the y is not, is a function. Example: y = -3x^2 + 2x
But a parabola which opens up or down, where the x is squared and the y is not, is a function. Example: y = -3x^2 + 2x
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Horizontal parabolas are not functions. The equation for a horizontal parabola has the form
x = a(y−k)² + h
Vertical parabols are functions. The equation for a vertical parabola has the form
y = a(x−h)² + k
x = a(y−k)² + h
Vertical parabols are functions. The equation for a vertical parabola has the form
y = a(x−h)² + k