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Draw a function!
05-17-2015, 08:23 AM
Post: #21
RE: Draw a function!
(05-17-2015 04:06 AM)Joe Horn Wrote:  In general, the best way to learn ANYTHING (including math) is by playing with it. So anything that encourages students to play with math is a teacher's dream come true.

I agree!

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05-17-2015, 03:08 PM
Post: #22
RE: Draw a function!
It took me about 5 minutes to update my HP Connectivity Kit, Virtual Calculator and Prime physical machine.
(Windows 7 and USB2 port)

Then, in a matter of fractions of a second, my Prime physical machine recognized linear, trigonometric, exponential and logarithm functions from my rudimentary sketching.

Then I tried to design a square wave, but it gave me a nice informative "Function not recognized" message.
A circle is not recognized or it is redesigned as an exponential.
A triangle waveform is redesigned as sinusoidal.
A sawtooth waveform is not recognized or is redesigned as sinusoidal.

Still, this is an unique and impressive feature that seems to be useful to learn math in schools, or to be used just to impress your friends at work, especially when we are talking about a pocket calculator device.

Jose Mesquita
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05-17-2015, 06:15 PM
Post: #23
RE: Draw a function!
(05-17-2015 08:23 AM)salvomic Wrote:  
(05-17-2015 04:06 AM)Joe Horn Wrote:  In general, the best way to learn ANYTHING (including math) is by playing with it. So anything that encourages students to play with math is a teacher's dream come true.

I agree!

Agree as well. To borrow from my alma matter (Cal Poly Pomona), Learn By Doing.
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05-19-2015, 07:53 AM
Post: #24
RE: Draw a function!
Is there a way of translating (moving) a drawn function by hand, in a similar way that it works in linear/quadratic/trig explorers?

Tim explained why it may be undesirable to be able to adjust datapoints in the scatter point, but with the graph I think it would be OK?

Cheers!
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05-19-2015, 02:30 PM
Post: #25
RE: Draw a function!
(05-19-2015 07:53 AM)mcjtom Wrote:  Is there a way of translating (moving) a drawn function by hand, in a similar way that it works in linear/quadratic/trig explorers?

Tim explained why it may be undesirable to be able to adjust datapoints in the scatter point, but with the graph I think it would be OK?

Cheers!

Not at this time. Yes, we know that would be a good thing. :-)

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
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05-19-2015, 08:28 PM
Post: #26
RE: Draw a function!
The biggest idea ever!!! The old HP graph calculators only sketch a function if you give the function...But recognizing the function if you sketch a graph is the function I was expecting on HP Prime since the beginning!!!
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05-19-2015, 08:54 PM
Post: #27
RE: Draw a function!
Amazing!

Can this be added to the advanced graphics too?

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05-19-2015, 11:00 PM
Post: #28
RE: Draw a function!
Very impressive, thank you.

Here is, if I may, a suggestion for another graphing device for the future. Touching in \(n+1\) points on the screen, \((x_0,,y_0), \ldots, (x_n,y_n)\), the HP Prime displays the graph of the polynomial \(p\) of degree \(\le n\) such that \(p(x_k)=y_k\) for all \(0\le k\le n\). Can it be done?
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05-20-2015, 03:00 AM
Post: #29
RE: Draw a function!
(05-19-2015 11:00 PM)Alberto Candel Wrote:  Very impressive, thank you.

Here is, if I may, a suggestion for another graphing device for the future. Touching in \(n+1\) points on the screen, \((x_0,,y_0), \ldots, (x_n,y_n)\), the HP Prime displays the graph of the polynomial \(p\) of degree \(\le n\) such that \(p(x_k)=y_k\) for all \(0\le k\le n\). Can it be done?

That would nice, and easy to program, since this function is already built in:

simplify(lagrange([[x0,...,xn], [y0,...,yn]]) --> polynomial which passes through those points.

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05-20-2015, 06:16 AM
Post: #30
RE: Draw a function!
(05-14-2015 10:46 AM)CR Haeger Wrote:  …For next update consider letting user populate XY graph with "dots" by finger…

(05-14-2015 07:55 PM)salvomic Wrote:  …As other user said in another post, it would be nice also could "tap" some point with finger then have an interpolation of the curve…

(05-19-2015 11:00 PM)Alberto Candel Wrote:  …Touching in \(n+1\) points on the screen, \((x_0,,y_0), \ldots, (x_n,y_n)\), the HP Prime displays the graph of the polynomial \(p\) of degree \(\le n\) such that \(p(x_k)=y_k\) for all \(0\le k\le n\). Can it be done?

Since the recognition doesn't occur until all fingers are "up", one can draw little curve snippets that are spatially separated if two fingers are used. The 7820 firmware does require a minimum amount of sketching to be done for recognition to be attempted (a certain # of pixels to be brushed, not a minimum size bounding box on brushed pixels).
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05-20-2015, 10:12 AM
Post: #31
RE: Draw a function!
Okay, now that I have access to a PC I could finally try this feature.
Experience is very poor with the mouse: for some reasons it is extremely slow and it is difficult to draw something smoothly.

Now I'm confused again with the Prime market. It is clear that it is for students and not engineers but to me this tool is really targeting young children while the Prime is way too advanced and expensive for such an audience.
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05-20-2015, 10:31 AM
Post: #32
RE: Draw a function!
(05-20-2015 06:16 AM)jte Wrote:  
(05-14-2015 07:55 PM)salvomic Wrote:  …As other user said in another post, it would be nice also could "tap" some point with finger then have an interpolation of the curve…

Since the recognition doesn't occur until all fingers are "up", one can draw little curve snippets that are spatially separated if two fingers are used. The 7820 firmware does require a minimum amount of sketching to be done for recognition to be attempted (a certain # of pixels to be brushed, not a minimum size bounding box on brushed pixels).

I'm trying, something more happens, I hope they'll add some functions type, as hyperbola, for example...

I'm having a better experience with a "conductive" pen, like those for iPhone, much precise that my huge finger Smile

Salvo

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05-20-2015, 08:33 PM
Post: #33
RE: Draw a function!
Little video about this great functionality:




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05-21-2015, 12:20 AM
Post: #34
RE: Draw a function!
(05-20-2015 10:12 AM)Tugdual Wrote:  … for some reasons it is extremely slow and it is difficult to draw something smoothly.

What part is extremely slow? A little more detail here could help the developers.

Are drawings noticeably less smooth than those produced using the pencil tool in MS Paint?
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05-21-2015, 01:11 PM
Post: #35
RE: Draw a function!
(05-20-2015 08:33 PM)eried Wrote:  Little video about this great functionality:




Great video, and now a I subscriber to your YT page.
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05-21-2015, 09:14 PM (This post was last modified: 05-21-2015 09:16 PM by jte.)
Post: #36
RE: Draw a function!
(05-15-2015 11:48 AM)ww63 Wrote:  When i try to sketch a hyperbolic function (like 1/x) it only finds a logarithmic or quadratic function, but no hyperbolic.

I think, you should add theese functional call too.

(05-20-2015 10:31 AM)salvomic Wrote:  … I'm trying, something more happens, I hope they'll add some functions type, as hyperbola, for example…

(05-17-2015 03:08 PM)jebem Wrote:  
Then I tried to design a square wave, but it gave me a nice informative "Function not recognized" message.
A circle is not recognized or it is redesigned as an exponential.
A triangle waveform is redesigned as sinusoidal.
A sawtooth waveform is not recognized or is redesigned as sinusoidal.

For a circle, were you thinking of √(A^2-(X-B)^2)?

Are there other forms of interest? I thought A*|X+B| could be nice.

With a large number of recognized forms it is more likely that there will be multiple good matches (and therefore harder to discern user intent). Also keep in mind that some forms are more amenable to incremental computation than others (how much computation is done while the curve is being sketched vs. done once the last finger is lifted).
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12-14-2016, 01:59 PM
Post: #37
RE: Draw a function!
I have a question about the Transform feature in the Plot view Function menu. The translation and dilation work really well! But the result is not automatically simplified. The expression can get quite messy after a few transformations. The manual claims that there is a Form soft menu button that, if used, will simplify the expression and round the coefficients but I don't see that button.

I copied the formula and then tried to use CAS algebra functions (simplify, collect, expand, and factor) but the result was always evaluated with X=0, even when there was no X variable. I get the same result in both the Home and the CAS environments.

How should I simplify this expression? -0.03*(X-2)^3-0.14*(X-2)^2+(X-2)+3+3.4
I know that there is something simple and easy that I am missing!
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12-14-2016, 03:14 PM
Post: #38
RE: Draw a function!
Tim wrote: This is setup for greater things later.

As I know my drawing skills are poor, one extension to this feature I would like to see in the future would be a "what graph is that" feature working from a .jpg rather than a sketch - comparable to some translation apps that can translate road signs etc. from camera input rather than text.
Of course, the emulator/PC versions could grab the .jpg straight from the camera Smile

Stephen Lewkowicz (G1CMZ)
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12-14-2016, 04:00 PM
Post: #39
RE: Draw a function!
(12-14-2016 01:59 PM)mark4flies Wrote:  How should I simplify this expression? -0.03*(X-2)^3-0.14*(X-2)^2+(X-2)+3+3.4
I know that there is something simple and easy that I am missing!

The simple and easy that is missing is actually on our end. We weren't happy with the simplification code for that specific type (cubics) yet, so it wasn't enabled. It will be turned on at some point in the future.

All the other forms do work however.

TW

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12-14-2016, 10:28 PM
Post: #40
RE: Draw a function!
Instead of drawing with your fat finger, you can use an Adonit pen. Works for me.
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