plot a vertical line

[Rose]

Hi,

I am sorry for my english.
I want to plot a vertical line. I can draw a horisontal line by doing
f1=lambda x:1.
But when I do f1=lambda y:1 it do the same thing, and when I try with
Infinity(like if a do a circle in \mathbb(C), who past by (1,0) and
(1,infinity), I got some error.

Thanks,

Rose

[William Stein]

Here is an example of drawing a vertical line:

sage: line([(1/2,-2), (1/2,2)])

[Jason Grout]

Try doing a parametric plot:

var('t')
parametric_plot( (3,t), -10,10)

(that is off the top of my head, I haven't checked it to make sure it
works...)

Thanks,

Jason

[Rose]

On 10 mai, 22:47, "William Stein" <wst...@gmail.com> wrote:

> Here is an example of drawing a vertical line:
>
> sage: line([(1/2,-2), (1/2,2)])

Wow that answer was fast,

Well if there a way to name it without drawing it (because I need to
put it in an if and I don't want it to by show anytime, like it does
with line (I don't know why line is drawing it, and I do not fine this
function in the documentation)).

Thanks for answering, even if I don't write well in english.

[Rose]

> Try doing a parametric plot:
>
> var('t')
> parametric_plot( (3,t), -10,10)
>

Heeeee, I don't even understand what is a parametric plot (and what I
found in SAGE literature is to complex for me). Can you please
explain.

Thanks.

Rose

[William Stein]

On Sat, May 10, 2008 at 8:13 PM, Rose <pinkwo...@gmail.com> wrote:
>
>
>
> On 10 mai, 22:47, "William Stein" <wst...@gmail.com> wrote:
>
>> Here is an example of drawing a vertical line:
>>
>> sage: line([(1/2,-2), (1/2,2)])
>
> Wow that answer was fast,
>
> Well if there a way to name it without drawing it (because I need to
> put it in an if and I don't want it to by show anytime, like it does
> with line (I don't know why line is drawing it, and I do not fine this
> function in the documentation)).

1. Type line? for docs on line.
2. An example of "naming it", and showing only in an if:

L = line([(1/2,-2), (1/2,2)])
if 1 == 1:
L.show()

> Thanks for answering, even if I don't write well in english.
> >
>

--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org

[Rose]

Rose a écrit :

> On 10 mai, 22:47, "William Stein" <wst...@gmail.com> wrote:
>
> > Here is an example of drawing a vertical line:
> >
> > sage: line([(1/2,-2), (1/2,2)])
>
> Wow that answer was fast,
>
> Well if there a way to name it without drawing it (because I need to
> put it in an if

Oh well my problem is not because it is in a if, I can not do a ==
Infinity, I don't understand why!

[Jason Grout]

Could you post the code that you have and explain what you are trying to
do with it?

Thanks,

Jason

[Jason Grout]

You can look it up in an algebra book or calculus book for more details,
but basically, the command above is saying to plot the points (3, t) for
any t between -10 and 10. In other words, plot points with x-coordinate
3 and y-coordinate "t", where t goes between -10 and 10.

That said, William's suggestion of using the line command might be easier.

Jason

[Rose]

On 10 mai, 23:33, Jason Grout <jason-s...@creativetrax.com> wrote:
> Could you post the code that you have and explain what you are trying to
> do with it?

Ohlala nothing works tonight, I am going to post it tomorow,
I hope you will help me then.

Thanks in advance.

Rose

[Rose]

On 10 mai, 23:33, Jason Grout <jason-s...@creativetrax.com> wrote:

> Could you post the code that you have and explain what you are trying to
> do with it?

Well I did it this morning. This is what I was triing to do:

sage: def creer_droite_h(a,b):
....: if a>b:
....: return creer_droite_h(b,a)
....: if b==Infinity:
....: y=line([(a,-2), (a,2)])
....: return plot(y,a-2,a+2)
....: centre=(a+b)/2
....: rayon=b-centre
....: y = lambda x:sqrt(rayon^2-(x-centre)^2)
....: return plot(y,a,b)
....:

Thanks for the help!

[John Cremona]

Rose,

S'il est necessaire, il y a des gens qui lit sage-support qui
comprennent le francais et qui peuvent peut-etre explique des choses
en francais (sans accents)!

John

2008/5/11 Rose <pinkwo...@gmail.com>:

[Rose]

On 11 mai, 12:15, "John Cremona" <john.crem...@gmail.com> wrote:
> Rose,
>
> S'il est necessaire, il y a des gens qui lit sage-support qui
> comprennent le francais et qui peuvent peut-etre explique des choses
> en francais (sans accents)!
>

Merci pour l'information.