# Limiting Domain of Parabola Function

eugbug shared this question 11 months ago

What syntax do I use for limiting the domain of a function such as a parabola?

From the Wiki, I can do things like:

f(x) = If(x < 3, sin(x), x^2)

But does this only work if I explicitly enter an equation in this format into the algebra editor?

My parabola was drawn in the graphing editor and depends on the position of the focus and directrix. So in the algebra editor it is:

Parabola: Parabola (focus,directrix)

Should I assign the parabola function to a new function f(x) and then impose limits? Or is there another less clumsy way of doing this?

https://www.geogebra.org/cl...

1

I used this construct and it worked fine. h is a new function, and Parabola is a Parabola object:

h = if ( -5 < x < 5, Parabola)

1

must to know that function x^2 and parabola y=x^2 are diferent type of object.

function can be limited to interval [1,2] doing if(1<=x<=2,f)

an implicit function can be limited y = x² + If(-1 < x < 2, 0) ; the if comand limit the domain

if you have a parabola with name c then c is the implicit equation of parabola then you can write RightSide(c) + If(-1 < x < 2, 0) = LeftSide(c) in input bar for limiting the graph ( last trick was wrote by an user in the last mounth but i do not remember in what topic)

1
1

`But does this only work if I explicitly enter an equation in this format into the algebra editor? `

it works only if directrix is horizontal