fulld | mbot: Solve[x==2] |

centrx | it's % % Solve[x==2] |

mbot | centrx: {{x -> 2}} |

kmh | my brain hurts <----- monty python |

fulld | nice |

aidan | [c(az-b)] / [e(az+1)] == 0 |

fulld | % Solve[x==sin(72)] |

mbot | fulld: Solve::svars: Equations may not give solutions for all "solve" variables. {{sin -> x/72}} |

aidan | what can I do with that? I need to find an approximate expression for z |

fulld | aidan: if c==0, it could be anything |

aidan | az is a little more complicated than az |

fulld | if (az-b)==0 then z= b/a |

aidan | ah, so I can let both the bottom half and the top half == 0? |

fulld | no, you can let either factor of the top == 0 |

aidan | ah, of course ... gosh my fundamentals are shocking |

fulld | I'd like to find the exact cosine of 72, 360/7, and 40 as an algrbraic expression. Are any of those possible? |

aidan | so if I let c = 0, I get a trivial solution? |

fulld | aidan: yes |

Kasadkad`` | fulld: yes (also if you're using degrees, specify, since everyone uses radians) |

john_sheu | fulld: taylor series? |

fulld | Kasadkad``: yes these are degrees, sorry about that |

Kasadkad`` | fulld: At least I'm pretty sure it's possible to express those in terms of radicals |

fulld | I that that for some arguments, mathematica magically knows the answer -- but I'm too poor for that what techniques should I use to simplify the taylor series? |

Kasadkad`` | Taylor series? |

fulld | ooh, radicals could be good |

Kasadkad`` | I don't think the Taylor series will help you |

john_sheu | does Mathematica count as a "technique"? |

fulld | john_sheu: i wish i could Kasadkad``: if there anything other than basic trig identites I can use to put it in a radical form? |

Kasadkad`` | fulld: The brute force way to do it is to write cos(nx) as a polynomial in cos(x) |

fulld | Kasadkad``: is that Chebyshev polynomial? |

Kasadkad`` | e.g. cos(5x) = p(cos(x)) where p is a polynomial, and then p(cos(72)) = cos(360) = 1, so if you can solve that polynomial you're done Yeah |

fulld | cool, I reading the wiki now |