What is the directrix of the parabola given by the equation `x=y^2` ?

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lfryerda | High School Teacher | (Level 2) Educator

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The for the parabola `y^2=4px` , the focus is found at `x=p` .  This means for the parabola `y^2=x` , the focus is at `x=1/4` .  The directrix is then the line perpendicular to the line of symmetry and equidistant from the focus and the vertex.  

That means that the directrix is the line `x=-1/4`

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