Limiting Domain of Parabola Function
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?