see post #2 here
the x is not squared. i suppose you meant to type
now, you should know that if a parabola is in the form , the vertex is given by ...oh, you do know that. ok, moving on.
now we want to get this parabola to look like the form i used in the post i directed you to.
the form must look like
in this form, the focus is:
and the directrix is:
now,
the coefficient of y is 1, so where would the 4 come from? well, we can notice that
thus, we have
so, we have ....look familiar?
it seems you are not reading through my posts. first of all, i never said anything was k + p. neither the focus nor the directrix is k + p. the focus is a coordinate and the directrix is a horizontal line.
i am sorry, but i really do not see the problem you are having. i went through the algebraic manipulations and tried to make it plain. but let's try again.
...........this is the form we want
....... ......... .......
............this is the form we got our equation in
now, the focus is:
and the directrix is:
can you tell me what h, p and k are?