3
$\begingroup$

A line that cuts into a function is a secant line, and a line that just touches a function is a tangent line.

But what is the term for a line that does not touch the function?

Take the parabola: $$y=x^2$$

A secant line would be: $y=2$

A tangent line would be: $y=0$

But what would $y=-2$ be ?

This line does have a special name as I remember reading it somewhere before and being surprised that it had a name. But unfortunately I have since forgotten it.

I keep thinking extraneous line but I can't find that term anywhere in writing.

$\endgroup$
  • 2
    $\begingroup$ I really doubt that it has a name. It doesn't feel useful or significant enough. There may be some archaic term somewhere though. $\endgroup$ – Arthur Aug 20 '18 at 13:48
  • $\begingroup$ I thought that before too, but I came across its name a while ago but have since forgotten it. I'm fairly sure it does have a name. $\endgroup$ – Kantura Aug 20 '18 at 13:50
  • 2
    $\begingroup$ We can say "non-intersecting line". $\endgroup$ – user Aug 20 '18 at 13:52
  • 1
    $\begingroup$ Were you meaning asymptote? $\endgroup$ – Mohammad Zuhair Khan Aug 20 '18 at 15:03
2
$\begingroup$

I don't know if the direct translation gives the correct answer but here in Italy we say that the line is external. Direct translation also can give: outside line, but it doesn't sound very good!

| cite | improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ Or in Germany we say Secante, Tangente or Passante. $\endgroup$ – Dr. Sonnhard Graubner Aug 20 '18 at 14:02
  • 1
    $\begingroup$ Italy is practically the same: Secante, Tangente, Esterna! $\endgroup$ – Davide Morgante Aug 20 '18 at 14:02
  • 1
    $\begingroup$ (Comment because this is non worth a separate answer) Translating from the French would give : a non-secant line. $\endgroup$ – Evargalo Aug 20 '18 at 14:03
  • 1
    $\begingroup$ I think it comes from the Latin language, $\endgroup$ – Dr. Sonnhard Graubner Aug 20 '18 at 14:03
  • 2
    $\begingroup$ Yes this is true,nice, Latin language is very importend $\endgroup$ – Dr. Sonnhard Graubner Aug 20 '18 at 14:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.