2021-02-08 15:05:08 +0200 | commented answer | vector_field.apply_map before and after vector.display (weird behaviour) Your explanation makes sense, though I thought when the vector_field is called, as in the question, the corresponding representation of the field in spherical chart is updated. |

2021-02-08 14:54:22 +0200 | commented answer | Divergence of inverse square It would have been great, if it had given the dirac solution. |

2021-02-07 04:27:55 +0200 | asked a question | vector_field.apply_map before and after vector.display (weird behaviour) Hello, Recently, I have come a cross a very weird behaviour with vector_field.apply_map function. Here is the case: Consider the following code: Now, if I create a vector field, substitute ph with ph_1 and th with th_1, and then display the resultant vector as I get However, If I do the same, but this time if I add I get printed (as expected). Why does the display function affect the substitution? |

2021-02-07 00:15:43 +0200 | asked a question | Divergence of inverse square Hello, I tried to calculate the divergence of 1/r^2 Results is Can this be considered as a bug? |

2021-02-02 01:01:18 +0200 | received badge | ● Good Question (source) |

2021-02-01 14:26:50 +0200 | received badge | ● Nice Question (source) |

2021-02-01 12:30:45 +0200 | commented answer | subs in vector field I had the same confusion. There is the subs function, but doesn't do the job. Don't you guys think that this is a bug? |

2021-02-01 04:11:15 +0200 | asked a question | subs in vector field Hello, gives back the vector field without substituting the value of a How does the funciton subs work with vector fields? Thanks alot for your help. |

2021-01-30 23:43:42 +0200 | commented answer | 2 sets of coordinates in EuclideanSpace? Thank you so much! this is really awesome. I love the way sagemath handle these things. |

2021-01-30 23:42:57 +0200 | received badge | ● Supporter (source) |

2021-01-29 21:28:08 +0200 | asked a question | 2 sets of coordinates in EuclideanSpace? Hello, I would like to work with 2 vectors in EuclideanSpace each having x1,y1,z1 and x2,y2,z2 coordinates. I will be needing to switch back and forth between cartesian and spherical coordinates as well. As an example, say, (r1,0,0) -> (x1,y1,z1) while (r2,0,0)->(x2,y2,z2) in the same EuclideanSpace. How would one work with multiple vectors (with independent coordinates) in EuclideanSpace? Should one define 2 chart for spherical coordinates and 2 for cartesian coordinates? Or should one create 2 different EuclideanSpace and combine them (if possible)? |

2021-01-29 14:26:30 +0200 | commented answer | Matrix multiplication with a vector in EuclideanSpace Thank you very much. This really helped and saved me from a lot of trouble. |

2021-01-29 01:25:10 +0200 | asked a question | Matrix multiplication with a vector in EuclideanSpace Hello Oversimplified version of my question is "How can I multiply a vector with a matrix?" The only work around I could think of is or directly on the vector field With this approach I have to put the transformed components back in the vector field defined within EuclideanSpace. I would like to use EuclideanSpace to work with vectors. Is there an easy way to handle this? Basically I am looking for an easy way to transform a vector field defined in EuclideanSpace? Thanks in advance for your help. |

2020-07-06 20:18:16 +0200 | commented answer | plot_vector_field3d in spherical coordinates Is there a way to increase density of the vectors? It is also very slow. Is there a way to speed it up? |

2020-07-05 23:00:12 +0200 | answered a question | How do I solve cos(2*t)==sin(t) You could try which gives Z's are integers. |

2020-07-05 22:47:56 +0200 | asked a question | Metric of EuclideanSpace(3) in spherical frame I may have some conceptual misunderstandings, but here is the code I was expecting the diagonal elements of the metric to be What I am doing wrong? |

2020-07-05 22:29:52 +0200 | commented answer | plot_vector_field3d in spherical coordinates Thank you so much. Yep, I made typos. Sorry for that. The code was on another computer, I was typing it it. |

2020-07-04 19:02:31 +0200 | answered a question | How to find all maximum length lists with a nested and display? As the other contributors have said, you can simply use python. Just another version: |

2020-07-04 12:48:23 +0200 | asked a question | plot_vector_field3d in spherical coordinates Hello, How can I draw a vector field in spherical coordinates? For example This beutifully gives me a vector field as Now, I would like to plot this field in spherical coordinates I also tried out the |

2020-06-23 00:14:23 +0200 | received badge | ● Nice Question (source) |

2020-06-22 23:19:56 +0200 | commented answer | assume gives false for a<oo Thanks for the clarification. I think it is an important point of view. |

2020-06-22 18:52:47 +0200 | marked best answer | solve: Possible bug? Hello, This question is relevant to Question #2 in the topic "desolve: wrong solution?!". If Consider the following expression sol is [a == (-5/8)] Now, if we plug that back in f, this gives 1.00000000000000 - 1.73205080756888*I, where it ought to give -2 (if there is a solution) And I tried this with Mathematica also It returns an empty list {} for this, indicating that there is no solution. What is wrong with Sage's Update:
I tried |

2020-06-21 18:42:01 +0200 | asked a question | assume gives false for a<oo Hello Why does this code print |

2020-06-21 03:57:16 +0200 | received badge | ● Commentator |

2020-06-21 03:57:16 +0200 | commented question | Another: dirac_delta integration: possible bug? I looked at the code and tried to fix it to accomodate this problem but I wasn't very successful (though I learned a lot!)
I tried the following with your version, but I am getting am I using it wrong? (especially the assumptions?) |

2020-06-20 14:54:11 +0200 | commented answer | find the root of tan(x) I was looking for that too :) Thank you. Similarly, I came across which I think does the same. |

2020-06-20 14:39:59 +0200 | answered a question | find the root of tan(x) It would simply be and this returns However, if you need something more general like |

2020-06-20 00:05:19 +0200 | marked best answer | Integration of dirac_delta Hello, When I tried to integrate the following I get But when I integrate I get If I try the same with Mathematica, I get I get What is the reason of this behaviour of Sage? |

2020-06-20 00:05:19 +0200 | commented answer | Integration of dirac_delta Unfortunately, I think there are more bugs in Sage's integral with dirac_delta. I opened up a new thread for them. Another: dirac_delta integration: possible bug? |

2020-06-20 00:00:09 +0200 | edited question | Another: dirac_delta integration: possible bug? I think there is another problem with the integration of the dirac_delta in Sage: (previous problem is discussed in the thread Integration of dirac_delta) Here is the problem: returns and returns |