Is knowing the coordinates of the vertex of a parabola enough to determine the domain and range? If so, how?
Thank you!

Question

Is knowing the coordinates of the vertex of a parabola enough to determine the domain and range? If so, how?
Thank you!

anonymous · Answer

as long as you know which direction it opens

anonymous · Answer

Would that be determined if knowing whether the vertex is a maximum or a minimum?

directrix · Answer

Let's practice.

Give the domain and range of a parabola with vertex (1, -4). 

@Catseyeglint911  @lonnie455rich  And, the answer is ...?

anonymous · Answer

To be honest, I have no idea how to answer that.

isaiah.feynman · Answer

The vertex is only useful in finding range. The y co ordinate of the vertex is used.

anonymous · Answer

if we assume that it opens up or down we know that the domain is 
$$(-\infty,\infty)$$
and if it opens up the range would be
$$[-4,\infty)$$

anonymous · Answer

and yes if the vertex is a maximum it opens down if it is a minimum it opens up

anonymous · Answer

Thank you all so very much!! :D

anonymous · Answer

if you graph it, it should be painfully obvious.

anonymous · Answer

I unfortunately do not have the ability to graph currently.

anonymous · Answer

do you not have a piece of paper?

isaiah.feynman · Answer

http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html

directrix · Answer

This --> Give the domain and range of a parabola with vertex (1, -4). has no answer without additional information.   @Catseyeglint911 

Although, I am now thinking that for all parabolas that are functions, the domain will always be the set of Real numbers. The Range is the tricky part.

anonymous · Answer

yep, the answer is useless without assumptions or special conditions

directrix · Answer

@Isaiah.Feynman   This message from the calculator link you posted gives me pause in that there is no description of the software to be downloaded.

anonymous · Answer

I just use wolfram alpha if my calculator isn't around me

directrix · Answer

Is this question answerable:

Give the domain and range of a parabola with vertex (1, -4) where the vertex is a maximum of the function.

anonymous · Answer

yes because we know that it opens down

directrix · Answer

Domain is the set of Reals.
Range is what?    @lonnie455rich

directrix · Answer

@Catseyeglint911  I think that your question as originally posted has been answered in this thread. Do you agree? If so, what is the answer to your posted question?

anonymous · Answer

$$(-\infty,-4]$$ is the range