Re: Two questions
- To: mathgroup at smc.vnet.net
- Subject: [mg123926] Re: Two questions
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Fri, 30 Dec 2011 07:08:47 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201112290754.CAA21150@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
a) There is no Subscript in the first result, which is actually
Y[x_] = y[x] /. First[DSolve[y[x] - 1/2 x y'[x] == 0, y[x], x]]
x^2 C[1]
b) The second result was not "nothing". It was
-(Sqrt[-x^2 + 4 C[1]]/Sqrt[2])
as your own post reveals. If you mean the corresponding plot, there's
nothing wrong with that, either:
Yort[x_] = y[x] /. First[DSolve[y[x] - 1/2 x (-1/y'[x]) == 0, y[x], x]];
Plot[Yort[x] /. C[1] -> 20, {x, -2, 2}]
THIS plot would be empty, however:
Plot[Yort[x] /. C[1] -> -20, {x, -2, 2}]
because all the function values are Complex.
c) I see the same options for Copy As with the right mouse button and
Edit>Copy as, EXCEPT that Edit>Copy as has two additional ones: PDF and
Quicktime.
I don't know why the difference, but as a guess... the extras will be
rarely used, so cluttering the mouse menu with them is not worthwhile.
Bobby
On Thu, 29 Dec 2011 01:54:52 -0600, Miguel <misvrne at gmail.com> wrote:
> 1.- Plot question
>
> Let the differential equation:
>
> In[]: Y[x_]=y[x]/.First[DSolve[y[x]-1/2 x y'[x]==0,y[x],x]]
> Out[]: Subscript[c, 1] x^2
>
> In[]: Plot[Y[x]/.C[1]->20,{x,-2,2}]
> And yields a correct graphic.
>
> But
>
> In[]: Yort[x_]=y[x]/.First[DSolve[y[x]-1/2 x (-1/y'[x])==0,y[x],x]]
> Out[]: -(Sqrt[4 Subscript[c, 1]- x^2]/Sqrt[2])
>
> And yields nothing.
>
>
> 2.- Menu options question
> The menu options of Edit\CopyAs are PlainText, InputText, ... Bitmap,
> Metafile
> But, the menu options of secundary bottom mouse of CopyAs are PlainText,
> Cell Expression, Notebook Expression .
> I think that is very useful al options on the secundary mouse.
>
>
--
DrMajorBob at yahoo.com
- References:
- Two questions
- From: Miguel <misvrne@gmail.com>
- Two questions