# User Portlet

Discussions |
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Whatever I try, nothing works. Sort[Union[{"(+3k-1,-4n/3-3m+k-7/3)", "(+3k+1,-n-m+k)", "(+3k-1,-n-m+k-1)"}], OrderedQ[{#1, #2}] &] gives {"(+3k-1,-4n/3-3m+k-7/3)", "(+3k+1,-n-m+k)", "(+3k-1,-n-m+k-1)"} which makes no sense to me.... |

Unfortunately this is no option to me. This is just one of many similar computations and I need algebraic proof and not just numerical precision in these steps. |

I have a problem which I cannot solve efficiently. I have a list of half-planes, disks and exteriors of disks and know that the intersection defines a bounded object, which I want to draw. RegionPlot doesn't work as it takes too long and is also very... |

I was able to reproduce the bug. Just restart your kernel and evaluate the following commands exactly as they are (will take a minute or two). The problem seems to be related to my usage of the protected symbol E as a local variable in a Block... |

f(a,b,c) is a very complicated expression and z can be any integer. |

Yes, you are right, this is most probably the issue. |

You can find the answer at the documentation of ReleaseHold: "ReleaseHold removes only the outermost layer of Hold" So you would have to apply ReleaseHold several times (= number of layers) to get rid of all Holds. |

f[n_] := If[n == 1, 1, Sqrt[3 f[n - 1] - 1]] Limit[f[n], n -> Infinity] Evaluating these two lines makes the Mathematica 8.0 kernel crash. |

On Mathematica 8 the following sumSum[Floor[2/2^p], {p, 1, Infinity}]evaluates to 0, which is obviously wrong.Sum[Floor[2/2^p], {p, 1, 10}]evaluates correctly to 1. |