2021-07-29 14:18:27 +0200 answered a question Calculation with arbitrary precision but that integral seems to be computed symbolically. Nope. It's just that : it can't be expressed in terms of "e 2021-07-29 12:43:18 +0200 commented question Solutions to Equations over different fields To illustrate Frederic's answer: def buildit(p): if not p.is_prime(): raise DomainError("p must be prime !" 2021-07-15 17:31:05 +0200 commented question set_trace() analog for Sage Did you try import pdb;pdb.set_trace()in a Sage terminal ? 2021-07-13 10:03:11 +0200 commented question Gradient (nabla) This might be of some help... 2021-07-13 10:02:40 +0200 commented question Gradient (nabla) [This]https:/(/doc.sagemath.org/html/en/thematic_tutorials/vector_calculus/vector_calc_advanced.html) might be of some h 2021-07-13 10:00:57 +0200 commented question Gradient (nabla) This might be of some help... 2021-07-13 09:56:57 +0200 commented question Implicit derivative at a particular point Homework ? What do you mean ? 2021-07-13 09:56:45 +0200 commented question Implicit derivative at a particular point Homework ? What do you mean ? 2021-07-13 09:52:19 +0200 commented question Implicit derivative at a particular point Homework ? 2021-07-11 09:01:53 +0200 commented question Simplification of arctan2(f1,f2) expressions. Why should it ? 2021-07-11 08:59:23 +0200 marked best answer Are symbols guaranteed unique ? A raid test show that symbols (at least symbolic variables) are unique : sage: L=[var("y")] sage: L+=[var("y")] sage: bool(L[0]==L[1]) True sage: bool(L[0] is L[1]) True  The secod y has been created at the same place as the first. But other symbols do not seem to obey the same rules : sage: R1.=QQ[] sage: foo = t sage: R2.=QQbar[] sage: foo.parent() Univariate Polynomial Ring in t over Rational Field sage: t.parent() Multivariate Polynomial Ring in s, t, u over Algebraic Field sage: foo is t False # expected : the same object can't have two different parents. sage: foo == t True # less expected...  What is the meaning of == in the latter case ? It should be noted that those two case are slightly inconsistent ; they are also both inconsistent with : sage: foo = (x+y).variables()[0] sage: bar = (x+y).polynomial(SR).variables()[0] sage: foo.parent() Symbolic Ring sage: bar.parent() Multivariate Polynomial Ring in x, y over Symbolic Ring sage: foo is bar # expected : the same object can't have two different parents. False sage: foo is bar # also expected. False  2021-07-11 08:59:16 +0200 commented answer Are symbols guaranteed unique ? Thank you VERY MUCH !. Now, that's clear(er)... 2021-07-11 08:57:06 +0200 commented answer Solve cannot get algebraic answer without taking logarithm Ahem... sage: sympy.solve((8^(3*x)==16^(x+1))._sympy_(), x._sympy_()) [4/5, 4/5 - 4*I*pi/(5*log(2)), 4/5 - 2*I*pi/(5* 2021-07-10 16:03:52 +0200 asked a question Are symbols guaranteed unique ? Are symbols guaranteed unique ? A raid test show that symbols (at least symbolic variables) are unique : sage: L=[var(" 2021-07-10 00:57:26 +0200 commented answer Wrong result after using factor(): known Sage bug? Pleas see sage-support : Sage has trouble converting your semi-numerical expression into a pure symbolic one. This might 2021-07-10 00:55:54 +0200 commented answer Wrong result after using factor(): known Sage bug? Pleas see sage-support : Sage has trouble converting your semi-numerical expression into a pure symbolic one. This might 2021-07-08 18:51:33 +0200 commented answer Wrong result after using factor(): known Sage bug? I just formatted it across multiple lines for presentation in my question. Could you repost it UNformatted ? 2021-07-08 13:27:58 +0200 edited answer Wrong result after using factor(): known Sage bug? Not an answer, but a comment needing more room than allowed in a comment : sage: %cpaste Pasting code; enter '--' alone 2021-07-07 22:49:15 +0200 edited answer Wrong result after using factor(): known Sage bug? Not an answer, but a comment needing more room than allowed in a comment : sage: %cpaste Pasting code; enter '--' alone 2021-07-07 22:27:16 +0200 answered a question Wrong result after using factor(): known Sage bug? Not an answer, but a comment needing more room than allowed in a comment : sage: %cpaste Pasting code; enter '--' alone 2021-07-06 21:31:55 +0200 commented question Wrong result after using factor(): known Sage bug? Tour copy seems incorrect :sage: f(1).n() 1.39111866114058e-12 + 6.95559330500736e-6*I sage: F(1).n() 4.83802782246652 2021-07-01 23:44:31 +0200 commented question Consider the set of all symmetric matrices of a given size $n$ with entries lying in $\{0,1\}$ such that all diagonal entries are zeros in the matrices. Homework ? 2021-06-28 23:26:34 +0200 commented question Doubt about solve_ineq Answer your own quest by stating that " this is a misinterpretation of" yours. This may help the next poor sod that will 2021-06-28 07:19:38 +0200 received badge ● Famous Question (source) 2021-06-15 20:04:23 +0200 commented question assume causes a solving failure These bugs seem mutually independent : sage: var("a, b") (a, b) sage: assume(a, "real") sage: equation=[a+b==0] sage: s 2021-06-15 20:01:21 +0200 commented question assume causes a solving failure solve has two positional arguments : a (list of) equation(s) to solve, and a (list of) variable(s) to solve for. You 2021-06-15 19:58:35 +0200 commented question assume causes a solving failure solve has two positional arguments : a (list of) equation(s) to solve, and a (list of) variable(s) to solve for. You 2021-06-15 19:48:53 +0200 commented question Lazy evaluation of symbolic integration This seems to result from the change of variable name : sage: var('x,u,w') (x, u, w) sage: F(x)=integral((min_symbolic( 2021-06-15 18:04:29 +0200 commented question How to dynamically pass multivariables while constructing a IntegerModRing? Are we supposed to guess the relationship you with to establish between the ring an the number and nams of the variables 2021-06-10 21:04:14 +0200 answered a question Rewrite log in exponents What you want to do may or may no be legitimate. Read the introduction to this section of the Sympy documentation... 2021-06-10 19:55:46 +0200 received badge ● Nice Answer (source) 2021-06-09 16:52:50 +0200 commented question Finding a diagonal matrix for a given matrix This might be of some interest for you... as well as this answer. 2021-06-09 16:41:13 +0200 commented question Finding a diagonal matrix for a given matrix This might be of some interest for you... as well as this answer. 2021-06-09 16:40:54 +0200 commented question Finding a diagonal matrix for a given matrix This might be of some interest for you... as well as [this answer]https://ask.sagemath.org/question/10682/singular-value 2021-06-09 16:03:50 +0200 commented question Finding a diagonal matrix for a given matrix This might be of some interest for you... 2021-06-09 08:38:07 +0200 edited answer solving for the center of the real quaternions I do not know well the quaternion algebra implementation, so I may miss a better answer ; hence a workaround : sage: Q. 2021-06-09 08:25:47 +0200 answered a question solving for the center of the real quaternions I do not know well the quaternion algebra implementation, so I may miss a better answer ; hence a workaround : sage: Q. 2021-06-08 19:02:44 +0200 received badge ● Nice Answer (source) 2021-06-08 13:52:52 +0200 commented answer Beginner problem solving equations. I strongly recommend this book f you want to ease your beginnings with Sagemath... Also : state your answer explicitly 2021-06-08 13:51:17 +0200 commented answer Beginner problem solving equations. I strongly recommend this book f you want to ease your beginnings with Sagemath... 2021-06-07 21:51:03 +0200 commented answer why giac integrate result fail to be parsed when using letter e? If so, why doesn't this happen when ee is substituted to e ? Hmmm ? 2021-06-04 08:57:21 +0200 commented question Plot with no scale on the y axis IMNSHO, this is a (minor) bug in plot, and should be reported as such... 2021-06-04 08:51:50 +0200 answered a question why giac integrate result fail to be parsed when using letter e? This is basically the same issue as the recent one with "D", which denotesfricas' derivative operator : "e" has special 2021-06-02 11:56:05 +0200 commented question why ECL says: Error executing code in Maxima: expt: undefined: 0 to a negative exponent BTW : sage: integrate(x^(k-1)*e^(-x/theta)/(gamma(k)*theta^k), x) -x^k*gamma(k, x/theta)/(theta^k* 2021-06-02 11:49:10 +0200 commented question why ECL says: Error executing code in Maxima: expt: undefined: 0 to a negative exponent Thanks, but the default have changed from maxima to giac in current sagemath (it used to be maxima in earlier version 2021-06-02 11:48:48 +0200 commented question why ECL says: Error executing code in Maxima: expt: undefined: 0 to a negative exponent Thanks, but the default have changed from maxima to giac in current sagemath (it used to be maxima in earlier version 2021-05-25 17:46:02 +0200 received badge ● Good Answer (source) 2021-05-23 21:29:29 +0200 received badge ● Nice Answer (source) 2021-05-23 15:29:28 +0200 edited answer Are these integrate interface issues with Fricas known? Note : : the first part of this answer is partly misleading. see the "IMPORTANT EDIT" below for the real explanation... 2021-05-23 11:16:44 +0200 received badge ● Nice Answer (source)