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Question 913811: Can someone tell me what I'm supposed to do? I don't get it. I'm supposed to find the focus and directrix.
I have all of these formulas but I have no clue where to put what. It's starting to irritate me. A lot.
Found 2 solutions by josgarithmetic, lwsshak3:
Answer by josgarithmetic(39620)   (Show Source):
You can put this solution on YOUR website! This is not a solution, but just advice:
Study how the equation of a parabola is derived using the distance formula, the meaning and use of focus and directrix, and the definition of a parabola. Simplify the distance formula equation and check how the resulting formula appears. That would be how to derive the equation of a parabola.
What you want to do is work in the other direction, so you would use the parts the resulting derived parabola equation to find the focus and directrix.
Like I say, this is advice or guidance, but not the answer you requested.
Your textbook should show a very good derivation for the equation of a parabola. Say if otherwise.
Note that in your second equation, the vertex would have moved from the standard reference (0,0) to the new vertex point (-3,5).
Answer by lwsshak3(11628) (Show Source):
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