x = -1/2y squared - y - 4

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- Mar 3rd 2008, 05:06 AMbrittneyvparabolas
x = -1/2y squared - y - 4

- Mar 3rd 2008, 07:03 PMbrittneyvconic sections help please
x = -1/2y squared - y - 4

i need the vertex, x intercept, y intercepts and directrix...that would be marvelous. - Mar 4th 2008, 02:28 AMearboth
Re-write the equation into the vertex-directrix-form:

The vertex has the coordinates

Therefore the directrix has the equation d:

With your need for x-axis and y-axis I assume that you mean the x and y intercepts of the parabola:

x-intercept: y = 0:

y-intercept: x = 0:

The LHS is negative, the RHS is a square - but a square can't be negative and therefore there doesn't exist any y-intercept.

Another attempt: The vertex is left of the y-axis and the parabola opens to left. Therefore the parabola and the y-axis can't have a common point. Thus: No y-intercept.