50g

Hello,

I am studying the Fourier series,
And when I want to calculate a sum:
sum from 0 to infinity, 1/(2x+1)^4, and
the calculator gives me: PSI (0.5, 3)/96

But I must find : PI^4/96

So how I can find it?! if it's possible....

Thanks a lot

Nico

--- In 50g@yahoogroups.com, "OLLIVIER" <nicolas.ollivier@...> wrote:

>
> Hello,
>
> I am studying the Fourier series,
> And when I want to calculate a sum:
> sum from 0 to infinity, 1/(2x+1)^4, and
> the calculator gives me: PSI (0.5, 3)/96
>
> But I must find : PI^4/96
>
> So how I can find it?! if it's possible....
>
> Thanks a lot
>
> Nico
>

I'm guessing a flag setting. The easiest way I know to toggle between
Real and Complex is to hold down Left Shift, while still holding it
down hit Tool. To quickly toggle between Exact and Approximate, hold
down Right Shift, while still holding it down hit Enter. Another
possibility is Rigorous (Flag -119) or, perhaps quicker is Mode, CAS
(you'll can toggle Rigorous 5th line down).
To see all your flags type RCLF. Mine currently are, with Radians,
Decimal, Real, Approximate and Rigorous Off:
{ # 36028806751912944d# 0d# 58547911847313432d# 0d}
Another way to see this string is to hold down Left Shift, while still
holding it down hit Mode, (let up on Left Shift here) hit Flag, hit
Next, hit RCLF.

Here's a good discussion of Fourier Series on HP 49G (HP 50g will be
the same):
http://groups.google.com/group/comp.sys.hp48/browse_thread/thread/e8d9fc11260a6a6/3ce5ddb8aaea2082?hl=en&lnk=gst&q=Fourier+series#3ce5ddb8aaea2082

If this doesn't help, write back with a keystroke example of what
you're doing, along with your RCLF string.

Thanks a lot for your help.

But I don't understand "RCLF", what this??
I looked the flag :Radians,Decimal, Real, Approximate and Rigorous
Off. And it's ok.

And I've the other post, and it's about Fourier series, but I think my
problem is not a problem specific to the Fourier series, but more
about sum.

--- In 50g@yahoogroups.com, "OLLIVIER" <nicolas.ollivier@...> wrote:

>
> Thanks a lot for your help.
>
> But I don't understand "RCLF", what this??
> I looked the flag :Radians,Decimal, Real, Approximate and Rigorous
> Off. And it's ok.
>
> And I've the other post, and it's about Fourier series, but I think my
> problem is not a problem specific to the Fourier series, but more
> about sum.
>

I'm assuming you're in RPN mode. RCLF isn't about Fourier, it's about
general calc flags (modes). Flag settings can be crucial on how you
see your results. If you hold down ON and hit F3, your 50g will reboot
(DON'T do this yet, it will mess up your fonts!). The screen that then
comes up is what I consider to be the default, or "stack" display. At
this screen, type RCLF and hit Enter (if you're already at the stack
display, and you probably are, you don't need to reboot). Depending on
your font size, you may need to hit VIEW and use the the cursor keys
to see the whole string. RCLF is short for Recall Flags; this is how
your calc remembers all your flag settings. For a more thorough
written explanation of flags, take a look at this:
http://www.hpcalc.org/details.php?id=4884
A month or 2 ago, someone left URLs which led to a couple of great
tutorials for HP 50g for college kids (the 1st of which includes their
recommended flag settings):
http://www.thiel.edu/mathproject/CalculatorLessons/Default.htm
http://www.thiel.edu/mathproject/Itphpc/default.htm

If you have time, leave a keystroke by keystroke example of what
you're trying to do, along with your RCLF string.

--- In 50g@yahoogroups.com, "OLLIVIER" <nicolas.ollivier@...> wrote:

>
> Hello,
>
> I am studying the Fourier series,
> And when I want to calculate a sum:
> sum from 0 to infinity, 1/(2x+1)^4, and
> the calculator gives me: PSI (0.5, 3)/96
>
> But I must find : PI^4/96
>
> So how I can find it?! if it's possible....
>
> Thanks a lot
>
> Nico
>

When the calc is in Exact mode, the Eval result of this summation is
given in terms of the special function "PSI". Just hit Right Shift,
then Enter to see the numeric answer 1.01467...
I haven't found an easy way to have this answer displayed in terms of
Pi. Here's a thread that may give you some ideas, though:
http://groups.google.com/group/comp.sys.hp48/browse_thread/thread/14e5022c987b8ed5/49a291fcb828b26d#49a291fcb828b26d

My old TI-89 popped right out with Pi^4/96.