SOLUTION: Why does the x^2 coefficient in a parabola determine the direction it opens?

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Question 637180: Why does the x^2 coefficient in a parabola determine the direction it opens?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Why does the x^2 coefficient in a parabola determine the direction it opens?
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As x goes to + or - infinity, x^2 goes to +oo.
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So, if a is positive ax^2 will go to +oo and force the parabola to open UP.
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And, if a is negative ax^2 will go to -oo and force the parabola to dpen DOWN.
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Cheers,
Stan H.