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2020-06-01 16:43:50 -0600 | commented answer | extract coefficients from products and sums of descending products Thank you @rburing this was very helpful. I have been able to move forward with my computations. |

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2020-05-22 15:33:58 -0600 | asked a question | extract coefficients from products and sums of descending products I need to extract coefficients of $n$ from some powers, products and sums of descending products and their reciprocals. The first 5 terms (in $x$) of the descending product $(x)_y$ are $$ x^y \left (1 - \frac{y(y-1)}{2x} + \frac{y(y-1)(y-2)(3y-1)}{24x^2} - \frac{y^2(y - 1)^2(y - 2)(y - 3)}{48x^3} + \frac{y(y-1)(y-2)(y-3)(y-4)(15y^3-30y^2+5y+2)}{5760x^4}\right) $$ and the first 5 terms of its reciprocal are $$ x^{-y} \left(1 + \frac{y(y-1)}{2x} + \frac{y(y-1)(y+1)(3y-2)}{24x^2} + \frac{y^2(y-1)^2(y+1)(y+2)}{48x^3} + \frac{y(y-1)(y+1)(y+2)(y+3)(15y^3-15y^2-10y+8)}{5760x^4}\right) $$ I need to extract the coefficients of various powers of $n$ in expressions like $$ \frac{(l(v-1)-1)(v-1)l(l)_t}{(n-1)_{t+1}} - \left(\frac{(l(v-1)-1)(v-1)l(l)_t}{(n-1)_{t+1}}\right)^2 + \frac{n(v-1)l(l)_{2t}(l(v-1)-1)^2(l(v-1)-2)}{(n)_{2t+3}} $$ where $l = n/v$ and $n$, $t$ and $v$ are symbolic variables. To encapsulate these descending products and their powers I wrote but sagemath does not correctly compute the coefficients in $n$. In an attempt to figure this out I asked a question here about computing coefficients of $n$ correctly and you can see there a very simple instance of sagemath failing to compute the coefficient. In my question I tried to give the simplest situation, where I do not have powers, products nor sums of my descnding products and their reciprocals, but just enough to showcase the behaviour of sage that is getting me stuck. In his answer @dan_fulea suggests that I need to approach my problem differently. Can anyone please give me some advice about the best way to compute the coefficients of any given power of $n$ in expressions like mine. |

2020-04-20 17:54:21 -0600 | commented answer | find correct coefficients in $n$ thank you @dan_fulea. I am definitely open to trying to do my calculation a different way. My example was a simplification of what I am really trying to do. Essentially I have a number of different expressions of forms similar to the above and I have to take some sums and products of them and then afterwards I need to extract the coefficients of particular powers of n. I was getting incorrect answers in some small examples and identified the issue that way. What is the method you would recommend for doing what I describe? Thank you for your time and expertise. |

2020-02-26 17:59:22 -0600 | commented question | find correct coefficients in $n$ I just realised that it also has two separate coefficients for $n^{-t-4}$ and $n^{-t-3}$, so there are other issues with .coefficients() |

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2020-02-25 15:32:04 -0600 | asked a question | find correct coefficients in $n$ gives the answer: It seems to detect all the powers of $n$ properly except $n^{-t}$. How can I process this symbolic expression so that sagemath computes the coefficients of $n$ properly? |

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2019-04-06 07:23:50 -0600 | commented answer | evaluating derivative of implicit function thanks rburing |

2019-04-05 15:28:44 -0600 | asked a question | evaluating derivative of implicit function I am trying to evaluate the derivative of an implicitly defined function But I do not know how to substitute the value I found for rho(1) into the expression for the derivative |

2019-02-06 15:39:13 -0600 | asked a question | jupyter tutorial My university department is updating the instance of sagemath that we use to 8.6. This will use the new Jupyter interface. I have two questions about the upgrade: 1) The old instance of sage we are running has many users each with their own notebooks. How do we migrate the multi-user environment to sagemath with Jupyter? 2) All of our sagemath users will need to migrate to using Jupyter. Is there a good tutorial for using sagemath in Jupyter? The http://www.sagemath.org/help.html documentation and tutorials in sagemath's website still are referencing the old notebooks. thanks brett |

2019-02-05 10:23:52 -0600 | commented answer | firefox tab completion sagemath Is there a tutorial on using sagemath with the jupyter notebooks? I have figure out some of the basic stuff but I logged out and when I tried loging back in it asked me for a "token" and said that I could obtain the token by running "jupyter notebook list" but this command produced: Error executing Jupyter command 'notebook': [Errno 2] No such file or directory |

2019-02-05 10:05:47 -0600 | commented answer | firefox tab completion sagemath I have switched sage on the two computers I control to use jupyter, but the sage server that my university provides needs to be updated before it can run jupyter. In the mean time I am still looking for a tab-completion fix in the old notebook with Firefox. |

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2019-02-02 17:58:29 -0600 | asked a question | firefox tab completion sagemath I recently upgraded my computer to Ubuntu 18.10. I think this may have upgraded my Firefox to 65.0. Now in Firefox I have two new (unwanted) behaviours when I try to use tab-completion in the sagemath notebook, the browser moves the active element from the cell to the evaluate button. when I press [backspace] in an empty cell it used to delete the cell and move the cursor to the previous cell. I would use this to delete a series of empty cells. Now it does nothing.
google-chrome is working fine Is this a new behaviour in firefox, is it an OS/xorg issue or does it involve the sagemath notebook? |

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