Roots other than square roots in Emacs calc

Roots other than square roots in Emacs calc

[Teemu Likonen]

Emacs calc can calculate square roots with "Q" command or with sqrt(x).
How about other roots? How to get cube root, for example?

Re: Roots other than square roots in Emacs calc

[Xah Lee]

On Aug 25, 6:15 am, Teemu Likonen <tliko...@iki.fi> wrote:
> Emacs calc can calculate square roots with "Q" command or with sqrt(x).
> How about other roots? How to get cube root, for example?

raise it to 1/3 for cube root.

  Xah
∑ http://xahlee.org/

☄

Re: Roots other than square roots in Emacs calc

[Teemu Likonen]

On 2009-08-25 06:40 (-0700), Xah Lee wrote:

> On Aug 25, 6:15 am, Teemu Likonen <tliko...@iki.fi> wrote:
>> Emacs calc can calculate square roots with "Q" command or with
>> sqrt(x). How about other roots? How to get cube root, for example?
>
> raise it to 1/3 for cube root.

Ah, of course, stupid me.

But hey, I teach Finnish, not math. :-)

Re: Roots other than square roots in Emacs calc

[Xah Lee]

On Aug 25, 6:45 am, Teemu Likonen <tliko...@iki.fi> wrote:
> On 2009-08-25 06:40 (-0700), Xah Lee wrote:
>
> > On Aug 25, 6:15 am, Teemu Likonen <tliko...@iki.fi> wrote:
> >> Emacs calc can calculate square roots with "Q" command or with
> >> sqrt(x). How about other roots? How to get cube root, for example?
>
> > raise it to 1/3 for cube root.
>
> Ah, of course, stupid me.
>
> But hey, I teach Finnish, not math. :-)

few years ago i asked for how to do square root in comp.emacs and was
having a fit to boot, and they told me raise it to 1/2.

:D

 Xah

Re: Roots other than square roots in Emacs calc

[Jay Belanger]

>> > On Aug 25, 6:15 am, Teemu Likonen <tliko...@iki.fi> wrote:
>> >> Emacs calc can calculate square roots with "Q" command or with
>> >> sqrt(x). How about other roots? How to get cube root, for example?

The ^ command gives powers; with the inverse flag, I ^, you will get the
roots.  So, for example, to find the cube root of 27, you can enter
27 RET 3 I ^

> few years ago i asked for how to do square root in comp.emacs and was
> having a fit to boot, and they told me raise it to 1/2.

Someone may well have said that, but it was also pointed out that the
manual (under "Basic Arithmetic") clearly states that "Q" gives the
square root.

Re: Roots other than square roots in Emacs calc

[Teemu Likonen]

On 2009-08-25 09:16 (-0500), Jay Belanger wrote:

> The ^ command gives powers; with the inverse flag, I ^, you will get
> the roots. So, for example, to find the cube root of 27, you can enter
> 27 RET 3 I ^

Interesting. So, these are the basic options:

    27 RET 3 & ^
    27 RET 3 I ^

Re: Roots other than square roots in Emacs calc

[Jay Belanger]

Teemu Likonen <tlikonen@iki.fi> writes:
> On 2009-08-25 09:16 (-0500), Jay Belanger wrote:
>
>> The ^ command gives powers; with the inverse flag, I ^, you will get
>> the roots. So, for example, to find the cube root of 27, you can enter
>> 27 RET 3 I ^
>
> Interesting. So, these are the basic options:
>
>     27 RET 3 & ^
>     27 RET 3 I ^

Yes.  If you use the first option, you'd want to be in fraction mode so
you are taking 27 to the 1/3 power and not the 0.333333333333 power.
The second option doesn't depend on the mode.