graph rounding issue

[mjs]

I hope I am posting this correctly.

 

Ok, I have a graph that is rounding the results for the min/max. I have set the graph to show 4 decimal from the main menu, #5 Settings & Status --> #2 Settings --> #2 Graphs and Geometry.

 

I have tried both floating 4 and fixed four, but the TI-nSpire CAS rounds everytime. I should be getting a result of 103.4 but 103 is all that is displayed.

 

Function solving for: T(t) = -0.3t^2+2.4t+98.6, for T(4).

 

My input: f1(x) = -0.3(4)^2+2.4(4)+98.6

 

Working that by hand shows 103.4. On a more complex function or during a test I would rather spend time solving other problems than doing one like this by hand that should be able to be done in a few seconds on the calculator.

 

What am I missing?

 

I tried testing the floating and fixed settings by changing the function to: f1(x) = -0.3(4)^2+2.4(4)+98.6521 (I added .0521 to the 98.6) and in the graph for the function the display changes the forumla from f1(x) = -0.3(4)^2+2.4(4)+98.6 to f1(x) = -0.3(4)^2+2.4(4)+98.7

 

For some reason the rounding is occuring where it wants. In my formula the TI is deciding that 1 significant digit is enough on the constant in my function, but in the graph checking for max I don't get any to show up beyond the decimal.

 

Any advice?

 

TI-nSpire CAS, OS Version 2.1.0.631

 

 

Many thanks in advance for any help that anyone can provide.

 

mshideler

[John Hanna]

Try hovering your mouse cursor over the number and press the ‘plus’ key to display more decimal places.

 

John Hanna

jeh...@optonline.net

www.johnhanna.us

T³ - Teachers Teaching with Technology

"A cowchip is paradise to a fly."

 

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[Nelson Sousa]

Why are you entering f1(x) as that?

Why not enter it as it is, -0.3x^2+2.4x+98.6 and trace it? With graphs
settings as Float 4 you must see 103.4. I did.

There are a lot of different ways to do that:
1. plot the function, add a point over the function and change it's x
coordinate to 4. The y coordinate will be 103.4
2. Trace the function
3. Go to a calculator page and type f1(4).
And a bunch other more.

Check you settings, confirm that they're Float 4.

And, for the record, 103 has 3 significant digits, not 1.

Cheers,
Nelson

[mjs]

John you stud.

that was it. I wish someone would write a good book on the nSpire. the dummy book just is not cutting it for looking up little things like this.

"hovering your mouse cursor over the number and press the ‘plus’ key to display more decimal places" :-)

mshideler

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From: John Hanna <johne...@gmail.com>
To: tins...@googlegroups.com
Sent: Thu, February 3, 2011 5:51:58 PM
Subject: RE: [tinspire] graph rounding issue

[Andy Kemp]

Hi mjs,

I wrote a student guide for using the TI-Nspire with the IB.  But it would be of use in lots of different courses and tries to cover a lot of these types of tricks along the way...

The book is available as a free download from:

http://kemp.co/IBbook

Not sure if it what you are after but you find some useful bits in it...

The other one that is also worth a look was a guide published in the UK called First Steps with TI-Nspire which again tries to cover some of these hints and tips.  That one is available for free download from:

http://education.ti.com/sites/UK/downloads/pdf/First_Steps_with_TI-Nspire_web.pdf

Cheers

Andy

[Lana Golembeski]

Awesome!! Thank you!!

Sent from my iPhone

Lana

[mjs]

Those are nice PDFs. much better than the ones supplied with the calc on purchase for sure.

Thanks for sharing those.

---

From: Andy Kemp <an...@kemp.co>
To: tins...@googlegroups.com
Sent: Fri, February 4, 2011 12:55:28 AM
Subject: Re: [tinspire] graph rounding issue

[Travis]

1st edition CliffNotes black/yelllow page 34 has it.

On Feb 4, 5:59 am, mjs <mjs_...@yahoo.com> wrote:
> Those are nice PDFs. much better than the ones supplied with the calc on
> purchase for sure.
>
> Thanks for sharing those.
>
> ________________________________

> From: Andy Kemp <a...@kemp.co>

> To: tins...@googlegroups.com
> Sent: Fri, February 4, 2011 12:55:28 AM
> Subject: Re: [tinspire] graph rounding issue
>
> Hi mjs,
> I wrote a student guide for using the TI-Nspire with the IB.  But it would be of
> use in lots of different courses and tries to cover a lot of these types of
> tricks along the way...
>
> The book is available as a free download from:http://kemp.co/IBbook
>
> Not sure if it what you are after but you find some useful bits in it...
>
> The other one that is also worth a look was a guide published in the UK called
> First Steps with TI-Nspire which again tries to cover some of these hints and

> tips.  That one is available for free download from:http://education.ti.com/sites/UK/downloads/pdf/First_Steps_with_TI-Ns...
>
> Cheers
> Andy

>
> On Fri, Feb 4, 2011 at 1:17 AM, mjs <mjs_...@yahoo.com> wrote:
>
> John you stud.
>
> >that was it. I wish someone would write a good book on the nSpire. the dummy
> >book just is not cutting it for looking up little things like this.
>
> >"hovering your mouse cursor over the number and press the ‘plus’ key to display
> >more decimal places" :-)
>
> >mshideler
>
> ________________________________

> From: John Hanna <johneha...@gmail.com>

>
>
>
> >To: tins...@googlegroups.com
> >Sent: Thu, February 3, 2011 5:51:58 PM
> >Subject: RE: [tinspire] graph rounding issue
>
> >Try hovering your mouse cursor over the number and press the ‘plus’ key to
> >display more decimal places.
>
> >John Hanna

> >jeha...@optonline.net
> >www.johnhanna.us
> >T3- Teachers Teaching with Technology

> For more options, visit this group athttp://groups.google.com.au/group/tinspire?hl=en-GB?hl=en-GB

[Travis Bower]

and page 52 2nd edition from Oullette