50g

Does anyone have a program written for the HP 50G that will give all
complex roots of a number? For example,the cube roots of -1 are
{[1+sqrt(3)]/2, -1, and [1-sqrt(3)]/2 } but the HP 50G will give only
the first. Trying to evaluate the cube root of 2+11i it chokes
altogether though the answers are clearly {2+i, -1.866+1.232i
(approx), -0.1340-2.232i (approx)}.

Joe

Make sure you're in complex & approx modes, then SOLVEX the equation x^3 + 1 = 0

For the other case, SOLVEX the equation x^3-2-11*i=0

--- On Wed, 12/31/08, joecolannino <joecolannino@...> wrote:

> From: joecolannino <joecolannino@...>
> Subject: [50g] Complex Roots
> To: 50g@yahoogroups.com
> Date: Wednesday, December 31, 2008, 1:15 PM
> Does anyone have a program written for the HP 50G that will
> give all
> complex roots of a number? For example,the cube roots of
> -1 are
> {[1+sqrt(3)]/2, -1, and [1-sqrt(3)]/2 } but the HP 50G
> will give only
> the first. Trying to evaluate the cube root of 2+11i it
> chokes
> altogether though the answers are clearly {2+i,
> -1.866+1.232i
> (approx), -0.1340-2.232i (approx)}.
>
> Joe

Hello Joe, if you want to get the n root of a number b, you have to
solve the equation x^n-b=0, to solve this you have to use the command
PROOT which needs as argument a vector with the coefficients, in this
case [1 0...0 -b] and you get back a vector with all the roots, How
many zeros do you need in your vector? n-1 zeros. If you enter first b
and then n, your program can be something like this:
<<
-> n
<< 1 SWAP NEG
2 n
START
0 SWAP
NEXT
n 1 + ->ARRY PROOT

>>
>>

b can be real or complex and n an integer grater than 1.

Everybody in the group have a nice year.

Also note that if you've set the 'exact' mode, the
solution to x^2+1=0 will give the results in an algebraic
form.

And you don't have to have the '=0' part. I put it in to
make it easier to see what's going on.

--- In 50g@yahoogroups.com, "Joe Colannino"
<joecolannino@...> wrote:

>
> Don, that was really helpful. It will be easy enough

to write a program to

> do this automatically. When I do so, I'll share it

with the group. Thanks

> again!
>
>
>
> Joe
>
>
>
> _____
>
> From: 50g@yahoogroups.com [mailto:50g@

yahoogroups.com] On Behalf Of Don Hart

> Sent: Wednesday, December 31, 2008 10:56 PM
> To: 50g@yahoogroups.com
> Subject: Re: [50g] Complex Roots
>
>
>
> Make sure you're in complex & approx modes, then

SOLVEX the equation x^3 + 1

> = 0
>
> For the other case, SOLVEX the equation x^3-2-11*i=0
>
> --- On Wed, 12/31/08, joecolannino <joecolannino@
> <mailto:joecolannino%40sbcglobal.net> sbcglobal.net>

wrote:

>
> > From: joecolannino <joecolannino@

<mailto:joecolannino%40sbcglobal.net>

> sbcglobal.net>
> > Subject: [50g] Complex Roots
> > To: 50g@yahoogroups. <mailto:50g%40yahoogroups.com>

com

> > Date: Wednesday, December 31, 2008, 1:15 PM
> > Does anyone have a program written for the HP 50G

that will

> > give all
> > complex roots of a number? For example,the cube

roots of

> > -1 are
> > {[1+sqrt(3)]/2, -1, and [1-sqrt(3)]/2 } but the HP

50G

> > will give only
> > the first. Trying to evaluate the cube root of

2+11i it

> > chokes
> > altogether though the answers are clearly {2+i,
> > -1.866+1.232i
> > (approx), -0.1340-2.232i (approx)}.
> >
> > Joe
>