Hello. Please and I mean Please, help me know how to find the y value in a parabola. The y value should either be the highest or the lowest point in a positive or negative curved u. Thank you very much for your time in helping me solve this question.
The formula for the vertex of a parabola, which
is the highest or lowest point, whose equation is:
First we calculate the discriminant
.
then the vertex is
(
,
)
Example:
For the parabola
We can find a few points by selecting
arbitrary values for x, substituting
and finding the y-values.
For example, if we substitute
into
So we have the point (-1,5)
We can find others the same way.
I found (-3,-7), (-1,5), (0,8), (3,5), and (5,-7).
Let's plot those:
We compare this problem:
to
and find
,
,
To find the vertex, we first calculate the discriminant
.
then the vertex is
(
,
) =
(
,
) =
(
,
) =
(
,
) =
So we plot the vertex at (
,
)
and sketch in the parabola:
Edwin