What is the directrix of the parabola ?
Answer and explanation
Correct answer: C.
- Step 1: A parabola with equation opens horizontally to the right with vertex at .
- Step 2: Equate .
- Step 3: The directrix is a vertical line given by .
Answer
.
Why not the others: '' is the directrix for a vertical parabola opening upward (); '' is the line passing through the focus ; '' confuses both axis orientation and sign.
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