MizardX | Recursivly you could on each level check in which triangle the point goes. If it's in the middle one, you know that it's not in the fractal. Otherwise continue recursion. |

StyxAlso | Say that I know that there's a chance p that it will rain today. If it rains today, there's a chance alpha that it rains tomorrow (conditional prob.). If it doesn't rain today, there's a chance beta that it doesn't rain tomorrow. What is the chance that it rains tomorrow? |

Olathe | You could determine if it's on a triangle boundary line or not. You can take the x position in binary to determine which removed triangles to check. Rotate the triangle 120 degrees and repeat. And so on. If the triangles to check in each set will intersect to give one or zero triangles. That might only work for rational points, though. |

prettytoney | Hi. |

logic_grrl | i am having trouble trying to understand how to break down some propositions for automated theorem proving |

tabber | Hi, if I have Sum(n=2..oo) x^(n) and im asked to compute thederivate, would that be Sum(n=2..oo) n*x^(n-1) ? |

Olathe | tabber: Yes, if the original sum and final sum is finite. |

chessguy | logic_grrl: can you be a little more specific? |

tabber | Olathe: thanks |

Olathe | tabber: No problem. |

logic_grrl | chessguy, www.people.fas.harvard.edu/~albert/cscie220/Asst6.pdf |

chessguy | logic_grrl: what about it? |

logic_grrl | chessguy, i just dont see how to go about it |

Olathe | logic_grrl: What is an example proposition and its breakdown ? |

logic_grrl | Olathe, well the easiest one is P and ~P |

chessguy | Olathe: they give example input |

logic_grrl | which cant be true |

Olathe | I hate PDFs. |

logic_grrl | but how do you show this using this method Olathe, http://209.85.165.104/search?q=cache:QFxw7TAsTQ0J:www.people.fas.harvard.edu/~albert/cscie220/Asst6.pdf+propositional+resolution+theorem+prover&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a ^ htl version |

chessguy | it looks to me like the problem is explained pretty thoroughly |

tabber | can anyone help me with exponental generating functions? anyone? |

Olathe | tabber: You have to tell us what problem you're having or we won't know if we can help you. |

tabber | ok, im asked to prove that psi''(x) = psi'(x) + psi(x), psi being the exponential generating function of the fibonacci sequence a_n = a_(n-1) + a_(n-2) for n>=2 and a_0 = a_1 = 1 would the egf be (Sum(n=2..oo) (a_(n-1)+a_(n-2))/n! * x^n) + x + 1 ? Is that correct? |

Olathe | I think it is. |

tabber | hmm im stuck at the sum .... |

Olathe | What do you mean ? psi'(x) + psi(x) ? |

tabber | yeah |

Olathe | You have psi'(x) ? |

tabber | i have Sum(n=2..oo) (a_(n-1)+a_(n-2))/n! * x^n + x + 1 + Sum(n=2..oo) (a_(n-1)+a_(n-2))/n! *nx^(n-1) |

Olathe | Alright. Add like terms. Like if you have x^3 + x^2 + x + 1 + 3x^3 + 2x^2 + x + 1, you can add it together. Same thing here. |

yi | off topic, any one familiar with tex and including graphics in it? http://pastie.textmate.org/45987 |