fccoelho's profile - activity

I want revert to a previous version of a worksheet in SMC.

I already found it in the history, now how can replace the current version with an older revision?

I noticed that while I was running some code in a wroksheet in sagemathcloud, a button with red letters saying: "Math processing error" appeared in the toolbar.

when I hover over it, a tooltip appears saying "define symbolic variable".

If I press the button, the following is inserted in the current cell:

%var x, theta

what does this mean? I didn't get any error messages in my code

In Wolfram's Alpha, when you enter some symbolic expression it will offer you many alternate forms, for example: http://www.wolframalpha.com/input/?i=...

is there a way to get similar results in Sage?

Is there a way to find Lyapunov functions candidates for a system of ODEs?

see for example: http://www.exampleproblems.com/wiki/i...

I know I can simply "do the math" given I have a candidate function, but I wonder if there is any way to quickly explore potential candidates.

Didn't work for me on Sage 6.1.1. But I found to be due to a bug in the `png` function on R 3.0.2

I have installed sage 5.11 but the server does not start from the app menu. However, when I start it from the console, everything works.

any hints?

A free parameter, automatically set when the solution is not unique. It should be r1 when you evaluate the cell the first time. Further evaluations increment to r2, r3, ....

Hi I am solving the following system:

var('C_at C_au C_bt C_bu I J k_1 k_2 gamma_1 gamma_2')
ss = solve([I-k_1*C_at,k_1*C_at - gamma_1*C_au, k_2*C_bu - gamma_2*C_bt, k_2*C_bu -   gamma_2*C_bt],C_at,C_au,C_bt,C_bu)
ss

and I get the following solution:

[[C_at=I/k_1,C_au=I/?_1,C_bt=k_2*r8/?_2,C_bu=r8]]

what is r8?

Another possibility, if your package is hosted in the python package index (pypi.python.org), is to run the following command:

./sage --python -m easy_install <package_name>