2021-07-01 13:52:53 +0100 received badge ● Nice Question (source) 2021-05-20 06:16:38 +0100 received badge ● Teacher (source) 2021-05-20 06:16:38 +0100 received badge ● Self-Learner (source) 2018-03-16 23:50:21 +0100 received badge ● Popular Question (source) 2017-06-21 09:17:01 +0100 received badge ● Good Question (source) 2017-06-21 09:16:58 +0100 received badge ● Famous Question (source) 2017-06-13 21:47:24 +0100 received badge ● Notable Question (source) 2017-03-28 03:59:06 +0100 received badge ● Notable Question (source) 2016-08-12 02:30:18 +0100 received badge ● Popular Question (source) 2016-07-22 20:48:46 +0100 received badge ● Famous Question (source) 2016-03-11 16:15:34 +0100 received badge ● Notable Question (source) 2016-01-16 01:18:50 +0100 received badge ● Notable Question (source) 2015-12-08 09:06:51 +0100 received badge ● Famous Question (source) 2015-05-03 07:39:32 +0100 received badge ● Popular Question (source) 2014-11-10 09:35:00 +0100 received badge ● Notable Question (source) 2014-06-29 03:15:10 +0100 marked best answer Symbolic solve Following the change of variable thread, I wanted to streamline the whole process. Namely, using the same example in the above thread, I'd like to say integral_def_change(x*cos(x^2+1), (x, 0, 2*pi), u == x^2 + 1, u)  The difference is, I wanted also Sage to automatically solve for x instead of providing x = sqrt(u - 1), say. But when I tried solve(u == x^2 + 1, x)[0].rhs()  the output was r1. 1- What exactly is r1 ?? A way out (see this thread) seems to make of the solution a function of u f(u) = solve(u == x^2 + 1, x)[0].rhs()  Now f is u |--> -sqrt(u - 1)  2- What can I do to get +sqrt(u - 1) instead? Is this related to the positive function question there? 2014-06-29 03:15:09 +0100 marked best answer Getting help inside Sage Sorry if it's a dumb question, folks. What are all the ways of getting help inside Sage? I would like some table like this: item?? | see code help(item) | see help about item  I ask this question because I only know the ?? and help() ways. But they don't always work: I tried simplify_full?? and help(simplify_full) but ... got errors! 2014-06-29 03:15:08 +0100 marked best answer Change of variable in an integration How to indicate a change of variable to Sage in an integration when Sage seems clueless? 2014-06-29 03:15:08 +0100 marked best answer Sympy integration algorithm towards -infinity Following achrzesz hint about integral's algorithm option, I tried (Sage 4.7.2): integral(1/x^2, x, -infinity, -1, algorithm='sympy')  Unfortunately, I got: Traceback (click to the left of this block for traceback) ... AttributeError: 'MinusInfinity' object has no attribute '_sympy_'  What's going wrong? 2014-06-29 03:15:08 +0100 marked best answer Keyboard layout in Sage appliance Hi all, I'm currently testing Sagemath on a Windows 7 box via sage appliance (4.7.2). I wanted to try the interactive shell out but it is not usable as my host keyboard layout is fr and the guest fedora box for sage uses en. A quick search pointed me to the system-config-keyboard command but too bad, it is not shipped with sage appliance 4.7.2. Any other hint ? Final solution (see below): change layout via sudo nano /etc/sysconfig/keyboard KEYTABLE="fr-latin1" MODEL="pc105+inet" LAYOUT="fr"  2014-06-29 03:15:07 +0100 marked best answer Interactive question in notebooks When trying to find some solution to the double integral problem and poking around with Sage (4.7.2), I stumbled upon this behavior: x,y,u,v,p,k=var('x,y,u,v,p,k') integrate(x+y^k, y)  output (resembles maxima interaction): Traceback (click to the left of this block for traceback) ... Is k+1 zero or nonzero?  How can I answer to this (with nonzero)? Update: I accept @god.one solution below as there seems no way as for now to interactively answer those maxima questions. 2014-05-22 05:04:48 +0100 received badge ● Popular Question (source) 2014-02-20 09:54:00 +0100 received badge ● Notable Question (source) 2014-02-11 09:46:35 +0100 received badge ● Popular Question (source) 2014-02-04 08:32:16 +0100 received badge ● Notable Question (source) 2014-01-28 08:44:12 +0100 received badge ● Popular Question (source) 2014-01-03 15:31:57 +0100 received badge ● Famous Question (source) 2013-08-28 09:13:38 +0100 marked best answer Symbolic solve sage: var('u') u sage: solve(u==x^2+1, x) [x == -sqrt(u - 1), x == sqrt(u - 1)]  So you could use [1] instead of [0] to get the "positive" one. I don't know how you got the r1 from this example, but the documentation for solve says, among other things:  If there is a parameter in the answer, that will show up as a new variable. In the following example, "r1" is a real free variable (because of the "r"): sage: solve([x+y == 3, 2*x+2*y == 6],x,y) [[x == -r1 + 3, y == r1]]  Hope this helps! 2013-07-14 19:43:59 +0100 received badge ● Famous Question (source) 2013-07-09 00:49:46 +0100 received badge ● Famous Question (source) 2013-03-28 05:27:35 +0100 received badge ● Popular Question (source) 2013-03-16 07:53:16 +0100 received badge ● Taxonomist 2013-01-07 14:33:40 +0100 received badge ● Notable Question (source) 2012-12-14 12:53:57 +0100 received badge ● Notable Question (source) 2012-12-10 06:49:55 +0100 received badge ● Popular Question (source) 2012-10-29 18:44:41 +0100 received badge ● Notable Question (source) 2012-10-09 10:04:16 +0100 received badge ● Popular Question (source)