http://www.mathstudio.net/forums/categories/iphone-ipad/p4/feed.rss Sat, 25 May 13 17:40:47 -0400 iPhone and iPad - MathStudio en-CA http://www.mathstudio.net/forums/discussion/862/question-about-setting-the-window-manually Tue, 08 Dec 2009 11:43:22 -0500 Justing6 862@/forums/discussions http://www.mathstudio.net/forums/discussion/863/dsolve Tue, 08 Dec 2009 16:31:41 -0500 ScottyV89 863@/forums/discussions
Everything seems to work for linear ODEs, however some simple linear ODEs don't return the correct sign for the constant, C1. I've actually found that whenever C1 stands by itself, it almost always has the opposite of the correct sign value.

One simple example could be: y' = x^2

The general solution to this ODE is: y = C1 + 1/3*x^3

SpaceTIme solves the ODE correctly, but with C1 having the opposite of the correct value.
________________________________
Script entered: DSolve(d(y(x),x)=x^2,y(x),no)
________________________________
Value returned: -C1 + (x^3 / 3)
________________________________

This can be recreated using many other 1st order linear ODEs, but I think that's unnecessary. The reason this is a problem besides the obvious is that some other 1st order linear ODEs return the correct value of C1 without the sign being flipped, leaving the user uncertain as to whether the answer is completely correct or if the sign of C1 has been flipped again.

An example of this is with the 1st order linear ODE: y' - 3y = x^2

The general solution of this ODE is y = C1*e^(3x) + 1/27(-9x^2 - 6x - 2)

SpaceTime correctly solves this with the solution completely expanded and with the correct value of C1: ((-x^2)/3 - 2x/9 + C1*e^(3x) - 2/27)

That's all the feedback I think I should give, as I've noticed on your Wiki page for it you've made a note that since this is a first implementation of the function, we should be expecting some future updates to help improve the function. Thanks again for a great mobile CAS.]]> http://www.mathstudio.net/forums/discussion/809/ti-84-comparison Tue, 10 Nov 2009 08:59:27 -0500 jaggkneio 809@/forums/discussions
1. Find the Y-intercepts of a graph with value. You are trying to find the point where the graph crosses the y-axis.
a.(ti-84 instructions) First Graph y=x^2+3x-5. Press 2nd CALC select 1: Value, hit enter then key =0, then enter.

2. Find the minimum (or maximum of a graph.
a. (ti-84 instructions) First Graph y=x^2+3x-5. Press 2nd CALC select 3: minimum, then you are prompted for a "left Bound/" Either key in and x value to left of the minimum. They you are prompted for a "Right Bound?" Move the cursor to the right of minimum. Then you are prompted for a "Guess?". Press Enter. The x and y values corresponding to the maximun are displayed at the bottom of the screen.

3. Finding any y-value for the corespnding x-value for y(1)=x^2+3x-5 .
a. (ti-84 instructions) Find the y-value for an input of x=-3. Press 2nd CALC, 1:value, enter. Then you will be asked to put in a value for x=-3 Press enter and should get x=-3 y=-5 at the bottom of your screen.

4. Finding any x-value for the corresponding y-value y(1)=x^2+3x-5 .
a. (ti-84 instructions) Find the x-value for the output of y=5. use the function y(1)=x^2+3x and then Graph y(2)=5. Ten press 2nd CALC, 5 intersect, enter. You will be asked for the First Curve. Just make sure that your cursor is close to where you think the intersection is. Press enter. You will be asked for the Second Curve. Press enter. Choose "Guess", enter. You should get x=2, y=5 at the bottom of the screen.


Thanks in advance!

Mike]]> http://www.mathstudio.net/forums/discussion/852/bug-on-3d-plots Sat, 28 Nov 2009 16:11:20 -0500 fabifgon 852@/forums/discussions
I found a bug on parametric3D, cylindrical, spherical plot, and some functions,
Plotting 'asin(y)' or 'acos(y)', if I put it in fullscreen and select 'Window' and scrolling down happen this:
http://img28.imageshack.us/img28/8137/97400881.jpg
http://img42.imageshack.us/img42/8647/wr1h.jpg
http://img42.imageshack.us/img42/3872/wr2k.jpg
http://img121.imageshack.us/img121/2972/wr3.jpg

Something like that happens on parametric3D, cylindrical and spherical plots, scrolling down and up 'Window':
http://img121.imageshack.us/img121/6365/websh.jpg
http://img121.imageshack.us/img121/4396/wr4s.jpg

Thanks!]]> http://www.mathstudio.net/forums/discussion/841/more-little-bugs Sun, 22 Nov 2009 11:12:19 -0500 fabifgon 841@/forums/discussions
When I enter the plot 'abs(sin(x))' and I check 'zeros', it doesn't show all zeros:
[attachment=1]web-2.jpg[/attachment]

And other bug, when I enter 'acosh(x)', it doesn't plot well, it must be a zero on x=1:
[attachment=0]web-1.jpg[/attachment]

Thanks!]]> http://www.mathstudio.net/forums/discussion/837/fourier-series Sat, 21 Nov 2009 05:32:12 -0500 ScottyV89 837@/forums/discussions http://www.mathstudio.net/forums/discussion/835/two-more-bugs-on-4-0-2 Fri, 20 Nov 2009 09:01:09 -0500 fabifgon 835@/forums/discussions
I found a crash when entering a regression plot, if a enter more than 3 sub square brackets (that happens too with more than 4, in spacetime update 3 for mac).
The other bug it's solving 'Pochhammer(-3/2,-5/2)', it must be 'ComplexInfinity':
[attachment=0]web.jpg[/attachment]

And when will be able update 3 for iPhone?

Thanks!]]> http://www.mathstudio.net/forums/discussion/832/error-hint-bug Thu, 19 Nov 2009 23:12:34 -0500 yym2 832@/forums/discussions This only appears on iphone edition.

Try Slove(s^2+s*R/L+1/LC=0) (it should be Slove(s^2+s*R/L+1/LC=0,s))]]> http://www.mathstudio.net/forums/discussion/817/problem-simplified-a-result Wed, 11 Nov 2009 13:51:02 -0500 fabifgon 817@/forums/discussions
When I'm calculating some entrophy properties, the result isn't simplified:
[attachment=1]web-1.jpg[/attachment]
[attachment=0]web.jpg[/attachment]
The simplification it's in the last entry.

And see too, in the second screenshot, the bug that I said you before with the color of parenthesis in diferent lines.

Thanks!]]> http://www.mathstudio.net/forums/discussion/814/how-do-you-use-powerexpand Tue, 10 Nov 2009 23:23:56 -0500 ScottyV89 814@/forums/discussions http://www.mathstudio.net/forums/discussion/802/feature-request Fri, 06 Nov 2009 01:06:20 -0500 evan 802@/forums/discussions
In my opinion, this is the by far the thing that would improve SpaceTime the most. If SpaceTime got this feature, I would deem it almost perfect.

Also, is there a function for finding maxima / minima on surfaces in 3-or-more-space? I may just be missing it.

Thanks!]]> http://www.mathstudio.net/forums/discussion/798/congrats-for-the-new-version-4-0-2-for-the-iphone Thu, 05 Nov 2009 15:37:10 -0500 rulo123 798@/forums/discussions http://www.mathstudio.net/forums/discussion/738/lngamma Sun, 11 Oct 2009 09:12:45 -0400 Rts4377 738@/forums/discussions
Otherwise, lngamma(x) works fine even for very large numbers wher I need it. Just not for x=odd/2.]]> http://www.mathstudio.net/forums/discussion/745/crash-on-new-spacetime-4-0-1 Wed, 14 Oct 2009 16:43:53 -0400 fabifgon 745@/forums/discussions http://www.mathstudio.net/forums/discussion/742/factorial-function Wed, 14 Oct 2009 08:50:45 -0400 fabifgon 742@/forums/discussions
Spacetime doesn't solve the integral and the derivate of factorial(x), please add this in the next update.

Thanks.]]> http://www.mathstudio.net/forums/discussion/771/bug-solving-beta-function Fri, 23 Oct 2009 09:39:38 -0400 fabifgon 771@/forums/discussions
When I enter 'Beta(-3/2,-5/2)' it returns complex infinity, but the well result it's zero.
Will be this fixed?

Thanks.]]> http://www.mathstudio.net/forums/discussion/728/will-the-next-update-be-released-this-month Sun, 04 Oct 2009 23:00:20 -0400 ScottyV89 728@/forums/discussions http://www.mathstudio.net/forums/discussion/751/download-to-complement-upload Thu, 15 Oct 2009 01:09:08 -0400 SolarSauna 751@/forums/discussions http://www.mathstudio.net/forums/discussion/762/congrats-to-chris-desalvo Sat, 17 Oct 2009 17:46:52 -0400 rulo123 762@/forums/discussions
Best regards Chris

and well done!!!!!!!

RAUL PADILLA]]> http://www.mathstudio.net/forums/discussion/732/beginning-user-question Wed, 07 Oct 2009 19:21:15 -0400 Justing6 732@/forums/discussions http://www.mathstudio.net/forums/discussion/753/parametric-plots-bug Thu, 15 Oct 2009 04:41:55 -0400 fabifgon 753@/forums/discussions
And other bug with parametric plots, enter the 'ParametricPlot' function by the catalog, now enter the variable x for example ('ParametricPlot(x)'), and press Enter, now press 'Entry->2D->Parametric' and appears a display bug. The same happens with ParametricPlot3D and 'Entry->3D->Parametric'.]]> http://www.mathstudio.net/forums/discussion/746/2d-polar-issue Wed, 14 Oct 2009 17:07:08 -0400 gaetano 746@/forums/discussions maybe there is a bug in Entry->2D->Polar.
If a number is entered the graph is shown in rectangular coordinates rather than polar ones as well as the legend on the right. E.g. entering 5 the graph results in a straight line instead of a circumference.
PolarPlot works fine

Thank you in advance
Gaetano]]> http://www.mathstudio.net/forums/discussion/747/text-entry Wed, 14 Oct 2009 17:42:52 -0400 stang06 747@/forums/discussions http://www.mathstudio.net/forums/discussion/744/screen-shot-on-iphone Wed, 14 Oct 2009 16:27:19 -0400 johnshimp 744@/forums/discussions
Thanks.]]> http://www.mathstudio.net/forums/discussion/752/tutorial-3d-graph-bug Thu, 15 Oct 2009 01:40:41 -0400 SolarSauna 752@/forums/discussions http://www.mathstudio.net/forums/discussion/736/salutation-and-compliments Sat, 10 Oct 2009 13:55:32 -0400 gaetano 736@/forums/discussions I am a new Spacetime user and forum subscriber.
My compliments to the development team, it is a very nice and powerful application and the iPhone integration is much better with the 4.0.1.

One curiosity, how do I enter a 2D vector? The wiki page looks not updated...

Thank you for your work
Gaetano]]> http://www.mathstudio.net/forums/discussion/740/virtual-keyboard Mon, 12 Oct 2009 06:19:57 -0400 allenholmes1 740@/forums/discussions Thanks!
Allen]]> http://www.mathstudio.net/forums/discussion/731/tutorial-bug Tue, 06 Oct 2009 23:52:11 -0400 Brett 731@/forums/discussions http://www.mathstudio.net/forums/discussion/713/bug-with-isprime- Sun, 20 Sep 2009 03:32:33 -0400 jmlouis 713@/forums/discussions IsPrime(49) give 1 (bug ?)
IsPrime(121) give 1 too
IsPrime(169) give 1 too ...
I suppose IsPrime(p^2) give 1 for all p prime number >= 7
Have I configurate something wrong ? I obtain this result both on my iPhone and on my Powerbook Mac.
(Thank's for help. And thank's for this beautiful program. SpaceTime is very nice. And so powerful that I'm sure the departure bugs will be fixed soon)]]> http://www.mathstudio.net/forums/discussion/692/one-more-bug Fri, 11 Sep 2009 17:31:30 -0400 home4jonathan 692@/forums/discussions