[sage-support] Re: Putting parentheses around -1.

2008-01-25 Thread John Cremona
On 25/01/2008, Paul Zimmermann <[EMAIL PROTECTED]> wrote: > > > In previous versions of Mathematica, there was a "RealOnly" package > > which defined odd roots as negative and printed "Nonreal" anytime a > > complex number was unavoidable. The idea was that you could simplify > > things for high

[sage-support] Re: Putting parentheses around -1.

2008-01-25 Thread Paul Zimmermann
> In previous versions of Mathematica, there was a "RealOnly" package > which defined odd roots as negative and printed "Nonreal" anytime a > complex number was unavoidable. The idea was that you could simplify > things for high school students or in situations in which you knew you > were on

[sage-support] Re: Putting parentheses around -1.

2008-01-24 Thread William Stein
On Jan 24, 2008 10:03 AM, Carl Witty <[EMAIL PROTECTED]> wrote: > > On Jan 23, 11:41 pm, Paul Zimmermann <[EMAIL PROTECTED]> wrote: > > Thus you have constructed a nice expression for 1: > > > > sage: sol[2].subs(a=1).right() > > (2/(3*sqrt(3)) + 10/27)^(1/3) - 2/(9*(2/(3*sqrt(3)) + 10/27)^(1/3))

[sage-support] Re: Putting parentheses around -1.

2008-01-24 Thread Carl Witty
On Jan 23, 11:41 pm, Paul Zimmermann <[EMAIL PROTECTED]> wrote: > Thus you have constructed a nice expression for 1: > > sage: sol[2].subs(a=1).right() > (2/(3*sqrt(3)) + 10/27)^(1/3) - 2/(9*(2/(3*sqrt(3)) + 10/27)^(1/3)) + 1/3 > > Quiz: how to simplify that expression to 1 within SAGE? I've tried

[sage-support] Re: Putting parentheses around -1.

2008-01-24 Thread Jason Grout
kcrisman wrote: > >> Thus you have constructed a nice expression for 1: >> >> sage: sol[2].subs(a=1).right() >> (2/(3*sqrt(3)) + 10/27)^(1/3) - 2/(9*(2/(3*sqrt(3)) + 10/27)^(1/3)) + 1/3 >> >> Quiz: how to simplify that expression to 1 within SAGE? I've tried simplify, >> and radical_simplify, but

[sage-support] Re: Putting parentheses around -1.

2008-01-24 Thread kcrisman
> Thus you have constructed a nice expression for 1: > > sage: sol[2].subs(a=1).right() > (2/(3*sqrt(3)) + 10/27)^(1/3) - 2/(9*(2/(3*sqrt(3)) + 10/27)^(1/3)) + 1/3 > > Quiz: how to simplify that expression to 1 within SAGE? I've tried simplify, > and radical_simplify, but neither succeeds... > >

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Paul Zimmermann
> > [...,..,x == (-1)^(1/3)*3^(1/3)] > > > > > > I ran into this issue while demonstrating the usefulness of the solve > > function in front of a class of students. That was quite 'fun' :-) > > > > Ted > > > It does seem strange that the answer that looked like it should be real is > actually not

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Ted Kosan
Jacob wrote: > It does seem strange that the answer that looked like it should be real is > actually not. If you have sage evaluate the first value in the returned > answers you see that despite its appearance it is the pure real number that > you desire. > > b[0].right().n() > > you get > -1.44

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Ted Kosan
> So why is solve placing parentheses around the 3rd root it returns if > it evaluates into an imaginary value? > > [...,..,x == (-1)^(1/3)*3^(1/3)] "around the 3rd root" should be "around the -1 in the 3rd root" Ted --~--~-~--~~~---~--~~ To post to this group, s

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Jacob Hicks
On Jan 23, 2008 9:19 PM, Ted Kosan <[EMAIL PROTECTED]> wrote: > > [...,..,x == (-1)^(1/3)*3^(1/3)] > > > I ran into this issue while demonstrating the usefulness of the solve > function in front of a class of students. That was quite 'fun' :-) > > Ted > It does seem strange that the answer that l

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Ted Kosan
William wrote: > Until a month ago (-1)^(1/3) would have given -1. This is the default > behavior dictated by Maxima. Then Paul Zimmerman complained > (with a great argument) that this was stupid, and Mike Hansen changed > the default Maxima behavior to what we currently have. He did > this by

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Ted Kosan
kcrisman wrote: >But what Ted really wanted was just the real cube root of -1. What I wanted was where the graph crossed the x axis as shown in the plot :-) Ted --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscri

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread William Stein
On Jan 23, 2008 5:50 PM, kcrisman <[EMAIL PROTECTED]> wrote: > > > > On Jan 23, 8:26 pm, "Ted Kosan" <[EMAIL PROTECTED]> wrote: > > Mike wrote: > > > It is due to the fact that ^ has a higher precedence than - in Python. > > > n(-1^(1/3)) is the same as n((-1^(1/3))). > > > > Okay, here is how I r

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread kcrisman
On Jan 23, 8:26 pm, "Ted Kosan" <[EMAIL PROTECTED]> wrote: > Mike wrote: > > It is due to the fact that ^ has a higher precedence than - in Python. > > n(-1^(1/3)) is the same as n((-1^(1/3))). > > Okay, here is how I ran into this: > >https://sage.ssu.portsmouth.oh.us:9000/home/pub/21/ > >

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Justin C. Walker
On Jan 23, 2008, at 5:26 PM, Ted Kosan wrote: > > Mike wrote: > >> It is due to the fact that ^ has a higher precedence than - in >> Python. >> n(-1^(1/3)) is the same as n((-1^(1/3))). > > Okay, here is how I ran into this: > > https://sage.ssu.portsmouth.oh.us:9000/home/pub/21/ > > What

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Ted Kosan
Mike wrote: > It is due to the fact that ^ has a higher precedence than - in Python. > n(-1^(1/3)) is the same as n((-1^(1/3))). Okay, here is how I ran into this: https://sage.ssu.portsmouth.oh.us:9000/home/pub/21/ What I expected to get was -1.44224957030741. Which result should it prod

[sage-support] Re: Putting parentheses around -1.

2008-01-23 Thread Mike Hansen
It is due to the fact that ^ has a higher precedence than - in Python. n(-1^(1/3)) is the same as n((-1^(1/3))). --Mike On Jan 23, 2008 5:04 PM, Ted Kosan <[EMAIL PROTECTED]> wrote: > > Does anyone have any thoughts on why the following 2 code samples give > different results?: > > #SAGE Version