Exact Fractions in Matrices

02012019, 02:39 PM
Post: #1




Exact Fractions in Matrices
Can matrices only display decimal approximations on the HP Prime?
Say I have the matrix [ [ 0.5, 0.6 ], [ 0.7, 0.8 ] ] and I want to display the matrix in the program as [ [ 1/2, 3/5 ], [ 7/10, 4/5 ] ]. A friend asked me how can we do this? QPI turns matrices into lists when converting to exact values. The command exact is ignored in Home Mode. I had no success with propfrac or partfrac. Is there a command that works like the [ a b/c ] key? Any help will be appreciated. Thank you. 

02012019, 04:47 PM
(This post was last modified: 02012019 04:58 PM by grsbanks.)
Post: #2




RE: Exact Fractions in Matrices  
02012019, 06:20 PM
Post: #3




RE: Exact Fractions in Matrices
It works in CAS with no probs.


02022019, 04:19 AM
Post: #4




RE: Exact Fractions in Matrices
This is awkward but it works in Home:
CAS("string(exact(M1))") <0ɸ0> Joe 

02022019, 04:21 PM
Post: #5




RE: Exact Fractions in Matrices
Hi!, Eddie :
Try by creating any algorithm with p/q Form, as ... 

02022019, 11:21 PM
Post: #6




RE: Exact Fractions in Matrices  
02032019, 11:37 PM
Post: #7




RE: Exact Fractions in Matrices
(02022019 11:21 PM)Eddie W. Shore Wrote: I'm surprised that QPI does not make all the entries of a matrices in exact fraction form. It does, but it also converts the matrix into a list of lists, because Home does not support symbolic matrices, only matrices of reals. So if you want a symbolic matrix, you'll either have to do it in CAS (or a CAS program), or convert the symbolic matrix into a form that Home can tolerate, such as a list of lists or a string. I personally like the QPI solution, even though its accuracy cannot be tuned as finely as the 'exact' function can. Disclaimer: I *think* the above is correct, but I've almost entirely given up trying to learn how to use the HP Prime. Attempting to wrap one's brain around a constantlymoving target which is also a shapeshifter surrounded by an intermittent cloaking device is painful. <0ɸ0> Joe 

02042019, 02:20 AM
Post: #8




RE: Exact Fractions in Matrices
(02032019 11:37 PM)Joe Horn Wrote: Disclaimer: I *think* the above is correct, but I've almost entirely given up trying to learn how to use the HP Prime. Attempting to wrap one's brain around a constantlymoving target which is also a shapeshifter surrounded by an intermittent cloaking device is painful. Yikes! But there is good news here, as this is almost certainly the first time I discovered something about an HP machine before Joe did... Bob Prosperi 

02042019, 02:04 PM
Post: #9




RE: Exact Fractions in Matrices
I would love to have a program command that works like the [a b/c] key.


02042019, 02:40 PM
Post: #10




RE: Exact Fractions in Matrices
Is it my imagination or is QPI() not documented anywhere (other than in the Toolbox Catlg)? I can't find it in the User Guide.
Cambridge, UK 41CL 12/15C DM15/16 71B 17B/BII/bII+ 28S 42S/DM42 48GX 50g 35s 30b/WP34S Prime G2 & Casios, Rockwell 18R :) 

02052019, 02:13 AM
Post: #11




RE: Exact Fractions in Matrices
(02042019 02:40 PM)cdmackay Wrote: Is it my imagination or is QPI() not documented anywhere (other than in the Toolbox Catlg)? I can't find it in the User Guide. Correct. Like many other recentlyadded functions (including my favorites, dfc and dfc2f), QPI has not yet been added to the User Guide. <0ɸ0> Joe 

02052019, 03:26 PM
Post: #12




RE: Exact Fractions in Matrices
(02052019 02:13 AM)Joe Horn Wrote:(02042019 02:40 PM)cdmackay Wrote: Is it my imagination or is QPI() not documented anywhere (other than in the Toolbox Catlg)? I can't find it in the User Guide. <scrambles to look those up…> thanks Joe. Some time ago someone posted a nice HTML version of the help file, which I downloaded. Sadly I can't remember whence it came, but it's the only doc I have that mentions QPI, and it's a lot easier to search than the one on the calc, even with the emulator. Cambridge, UK 41CL 12/15C DM15/16 71B 17B/BII/bII+ 28S 42S/DM42 48GX 50g 35s 30b/WP34S Prime G2 & Casios, Rockwell 18R :) 

02062019, 05:35 AM
Post: #13




RE: Exact Fractions in Matrices
(02052019 03:26 PM)cdmackay Wrote: Some time ago someone posted a nice HTML version of the help file, which I downloaded. Sadly I can't remember whence it came... Did you mean this thread? Geocaching Coords Solver, Number of triangles Puzzle 

02062019, 02:39 PM
(This post was last modified: 02062019 02:40 PM by cdmackay.)
Post: #14




RE: Exact Fractions in Matrices
(02062019 05:35 AM)chromos Wrote:(02052019 03:26 PM)cdmackay Wrote: Some time ago someone posted a nice HTML version of the help file, which I downloaded. Sadly I can't remember whence it came... oh! It was TimW, how embarrassing for me to forget. Yes, that was it, thanks very much indeed. edit: and your version too, thanks! Cambridge, UK 41CL 12/15C DM15/16 71B 17B/BII/bII+ 28S 42S/DM42 48GX 50g 35s 30b/WP34S Prime G2 & Casios, Rockwell 18R :) 

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