Pneuma

New to Wolfram Mathematica. I would like to obtain in a single graph the plot of the function 3x in the range {x,0,10}, followed by the plot of the function x^2 in the range {x,10,20}.

I could not find on the Plot help section the corresponding syntax to obtain that result. Any suggestions will be welcomed. Thanks in advance.

When working with Mathematica 9 I always get the tags

In[nn]:= for inputs and

Out[nn]= for outputs.

Is any way to avoid those tags? I want to produce a notebook without those auxiliary tags. Thanks in advance!

Recién llegado al Mac, busco un programa desarrollador de páginas web de tipo WYSIWYG. No se trata de construir páginas complejas. Mejor si es gratis, claro, pero consideraré las de pago si son buenas. Gracias por adelantado.

I have an iPad with the Kindle app installed (e-book reading), and I also have a Kindle PaperWhite device (the Amazon device to read e-books). Both Kindles have a Cloud and a Device libraries.

If I buy an e-book from Kindle store, I have it in both places, Cloud and Device. But if I take an e-book of my own in iPad, open it in Kindle app, then I can read it with the Kindle app in iPad, but it does not upload to the Kindle Cloud, so I cannot have it synchronized with my Kindle device.

Any suggestion? Does Amazon forbids this kind of e-book transfers?

Thanks in advance to you all.

(I apologize for my English, but I hope I made me understood).

In a text about Cosmology, trying to obtain the so called Fluid Equation, I read the formula of the first lay of thermodynamics:

dU = T dS - p dV

I realized that I forgot the exact meaning of that law, except that it expresses the conservation of energy. I suppose that T is the temperature, S the entropy, p stands for pressure an dV is the change of the volume. I do not know the name for U.

1) I see that p.dV is a work, but I cannot grasp the meaning of T dS. Could someone explain that to me?

2) The entropy S, was not a question of the second law? What is it role in the first law?

Thanks in advance.

I used to edit webpages with Kompozer, but it has been discontinued. I would like to know if there is a off-line webpage editor, wysiwyg tipe, for Linux Ubuntu (3.04 version). A simple one will be enough for me. Thanks in advance.

Google Desktop Search era una gran ayuda en Windows cuando se trataba de hallar documentos residentes en nuestro PC y que contienen una determinada palabra. Hablo en pasado porque al parecer Google tomó la decisión de no mantenerlo. ¿Existe alguna dirección desde la cual descargar la versión, aunque haya dejado de tener soporte, para Windows XP? ¿O ha sido sustituído por algún módulo equivalente, aunque no se cita nada en el blog correspondiente?

In expanding space, recession velocity keeps increasing with distance. Beyond a certain distance, known as the "Hubble distance", it exceeds the speed of light. But I read that Hubble distance increases with time. Any explanation?

Thanks in advance.

Herzprung-Russell diagram was first formed about 1903 (Hertzprung) and 1913 (Russell). At that time, only stars of our own Galaxy, the Milky Way. The question is: in its current version, does all of the stars of the diagram part of our Galaxy, or stars from other galaxies have been added?

Thanks in advance.

El diagrama de Hertzprung-Russell se confeccionó hacia 1903 (Hertzprung) y 1913 (Russell, de modo independiente). Entonces solamente se conocían las estrellas de nuestra Galaxia, la Vía Láctea. Pero en su versión actual, ¿se integran estrellas de otras galaxias en el diagrama?

In the Spanish League Soccer (we call it fútbol, from football), there is a Betting (known as Quiniela). We bet about the results of 15 matches, betting to 1 (host team wins), 2 (visitor team wins) or x (lets us say 0) (the result is a draw).

So there are 3^{15} (3¹⁵) potential combinations. The question is: supposing we bet random, just one result per match, what is the probability of getting N results OK?

I apologize for my poor English, but I hope I made me understood. Thanks in advance.

En el universo se tiene un enorme número de fotones. Debido a la expansión del espacio, la longitud de onda de dichos fotones se hace mayor, y por lo tanto su energía se reduce, conforme a la fórmula de Planck-Einstein:

ε = h ν = h c / λ,

Podemos pues concluir que el universo se enfría, pero, al no existir transferencia de energía con ningún otro cuerpo o espacio, parece que se viola el principio de conservación de la energía.

Alguna explicación?

Let us suppose that the universe is composed of photons. Due to the expansion of the space, the wavelength of photons becomes greater, and therefore its power is reduced:

ε = h ν = h c / λ,

according to Planck-Einstein formula. So we conclude that the universe cools but, if there is no heat transfer, that seems to violate the principle of conservation of energy.

Any explanation?

On 19 September 2005 was released the lead single of the British singer Katie Melua, with the still well known song "Nine Million Bycicles":

http://www.youtube.com/watch?v=DTy3WA0Pq8M

The second verse of the lyrics says

"We are 12 billion light-years from the edge.

That's a guess –

no-one can ever say it's true,

but I know that I will always be with you."

On 30 September 2005, Melua was criticized in The Guardian from the scientist (and writer) Simon Singh:

http://www.theguardian.com/education/2005/sep/30/h...

The ammended lyrics, as proposed by Singh was:

"We are 13.7 billion light-years from the edge of the observable universe, That's a good estimate with well-defined error bars, And with the available information, I predict that I will always be with you"

But I judge those sayings as actual blunders, for

a) Let us assume we understand by edge the point of the Big-Bang initial process, or the last scattering surface, close in time (380 thousand years) to the Big-Bang starting point.

b) So we could say we are 13.7 billion years from the edge (12 billion will sound better, by the way).

c) But saying that we are 12 or 13.7 billion light-years from the edge is a big error, for a light-year is a distance measure unit, not a time one. So we can say that light we are now receiving "has traveled" a distance of 13.7 billion light-years, but this does not mean at all that we are 13.7 light-years apart from the edge, for that means to ignore the space expansion.

But what astonish me the most it that no one in the scientific establishment criticized the Singh's amendment.

Am I right, or I'm missing something?

The image of the following link

http://en.wikipedia.org/wiki/File:Cobe-cosmic-back...

shows three steps that corrects the initial COBE data from the CBR. I would like to confirm my own interpretation of the process:

1) The initial data. Light redshif and blueshift means than we are moving from "northeast" to "southwest". I suppose it is our galaxy (maybe our sun adds its own velocity?) the one which is moving through the universe. If so, to which astronomical point are we moving to?

2) The second image shows a red belt. Is our galaxy the origin of that radiation? Why is it red?

3) The third image shows what seems to be big patches red or blue coloured. But I understood that the COBE measures accuracy was of the 200 μK, what is really very small.

Thanks in advance. I apologize for my poor English, but hope I made me understood.

This representation of the cosmic background radiation:

https://docs.google.com/file/d/0B369xwR-JYKkWm9rUl...

resembles that used to represent for instance the earth sphere. But actually it is a vision of the instant of last scattering. How should we interpret the image from the geometrical point of view? What indicates in this case the poles and the equator end points? Thanks in advance.

Linux Ubuntu 13.04. The Graph tool of LibreOffice Calc worked fine, but suddenly it stopped to work. I select the figures in a column, then press the Graph icon (or select the Graph option in Insert on the menu), but no columns or any other graph is shown. Nothing except the graph frame. ¿Any suggestion? Thanks in advance.

Tengo instalado Ubuntu 11.10 junto con Windows en el Disco 1, pero no está funcionando bien, debido a problemas con las actualizaciones previas. Quiero instalar Ubuntu 11.10 desde CD en el Disco2, y mantener las tres opciones. ¿Debo pedir instalarlo "alongside Windows" o como instalación nueva? Temo perder el menú de elección al arrancar.