On Wed, Jun 18, 2014 at 2:34 AM, <[email protected]> wrote: > This has been brought up many times before, but I'd like to bring up > the possibility of adding two commands to Sage: cuberoot(x) and > nthroot(x, n) >
Just to be clear, if you defined nthroot in the obvious way, the code would check for each evaluation if n is an integer, then if even or odd, right? Wouldn't that slow down a plot compared to what you have below? > The reason is that currently plot( x^(1/3), -5, 5) only shows values for > x>0, > and not for x<0. The current work-around recommended is > > plot(sign(x)*abs(x)^(1/3), -5, 5) > (Track ticket #11458) > > which replaced the hideous > > plot(lambda x: RR(x).nth_root(3), -5, 5, plot_points=20) > > This is true in classes like Precalculus and Calculus 1, where trying to > explain > workarounds like these would just really a headache for the instructor and > extremely fragile students. > > Also the cube root can occur in many other situations and applications. > This is urgent, because my textbook "Sage for Undergraduates" is due > at the American Mathematical Society on June 30th. > > The namespace is so huge, can't we just add two more commands? > > I suggest: > > def cuberoot(x): > return sign(x)*((x*sign(x))^(1/3)) > > Last but not least, links to previous demands for exactly this problem: > > https://www.mail-archive.com/[email protected]/msg11563.html > https://groups.google.com/forum/#!msg/sage-devel/_JeSMD-Kvfk/xeNstGrcvXQJ > https://groups.google.com/forum/#!topic/sage-support/icZ8ekC_P4Y > https://groups.google.com/forum/#!topic/sage-devel/_JeSMD-Kvfk > http://trac.sagemath.org/ticket/11458 > https://sage.uwstout.edu/home/pub/32/ > https://groups.google.com/forum/#!topic/sage-support/ZtRWScqMHMM > https://groups.google.com/forum/#!topic/sage-devel/_JeSMD-Kvfk > > -- > You received this message because you are subscribed to the Google Groups > "sage-edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sage-edu. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-edu. For more options, visit https://groups.google.com/d/optout.
