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anonymous

  • one year ago

how do I know when a parabola is or isn't a function?

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  1. Zale101
    • one year ago
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    By the vertical test, you can determine which functions are and not a function.

  2. anonymous
    • one year ago
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    and a vertical test is when...?

  3. Zale101
    • one year ago
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    The vertical line test determines if the graph passes vertical lines only 1, but not twice. For example, if we have a parabola. |dw:1441659261950:dw|

  4. Zale101
    • one year ago
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    The y values gets to be passed once when doing the vertical line test (refer to the bold dots)

  5. anonymous
    • one year ago
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    the parabola must open up or down. it cannot be rotated on any direction

  6. Zale101
    • one year ago
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    But if we have a side ways parabola. |dw:1441659344699:dw|

  7. Zale101
    • one year ago
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    The function does not pass the vertical line test because 2 y values are touched by the same x value.

  8. Zale101
    • one year ago
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    Therefore, the sideways parabola is not a function.

  9. Zale101
    • one year ago
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    Makes sense?

  10. amistre64
    • one year ago
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    a parabola is always a function .... its equation is not necessarily based on a coordinant axial system

  11. amistre64
    • one year ago
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    x = 4y^2 is a parabolic function. |dw:1441660077511:dw|

  12. Zale101
    • one year ago
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    The graph of x=4y^2 is sideways parabola but narrower. No?

  13. amistre64
    • one year ago
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    no, you see that I have drawn the y axis as the horizontal, and the x axis is vertical ... making y independant, and x dependant. 'sideways' is not relevant ... all parabolas can be oriented to open upward or downward

  14. amistre64
    • one year ago
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    |dw:1441662415252:dw| move the vertex to the origin, and rotate the 'graph'

  15. amistre64
    • one year ago
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    im sure the question did not have this in mind ... but still

  16. Zale101
    • one year ago
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    Oh yes, i noticed the change of the axis xD

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