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Classpad Doesnt't Solve Equation


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#1 neanderix

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Posted 03 February 2007 - 09:08 PM

my problem is the following:

given ist the equation
1/x + 1/y = 1/2
1/x - 1/y = 1/6

but i can do what i want to - Classpad won't solve it but just write it down.

I tried it with "solve":

solve({1/x + 1/y = 1/2,1/x - 1/y = 1/6},{x,y})

result after pressing "exe": {1/x + 1/y = 1/2,1/x - 1/y = 1/6}

I also Tried with the 2D-Iput-field {..| ... same result, the classpad refuses to *solve* the equation.

Why? Any idea?

Volker

#2 Guest_Guest_Johnet123_*_*

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Posted 03 February 2007 - 10:55 PM

Using OS version 3.01, and entering the problem as exactly as in your post, I arrived at the answer, {x=3,y=6}.

What version of OS are you using?

Johnet123

#3 neanderix

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Posted 04 February 2007 - 01:15 PM

Using OS version 3.01, and entering the problem as exactly as in your post, I arrived at the answer, {x=3,y=6}.

What version of OS are you using?

Johnet123


My OS ist 02.20.3000

But this should be regardless, because of the fact that some posters in the german casio-forum did this calculation and got the correct answer too.

I really don't know what to do. May be a wrong or missing setting?

Volker

ADD: Even the sample in the print-manual, page 2-7-39, won't do.
Excecutiong this sample my classpad shows as a result:
{12*x*y=5, 2*x-3*y=-8}

#4 The_AFX_Master

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Posted 04 February 2007 - 04:15 PM

But this should be regardless, because of the fact that some posters in the german casio-forum did this calculation and got the correct answer too.


isn't regardless, your OS (2.20), doesnt can solve non linear systems, only OS 3.0 can do it.
When the CP ''refuses'' to solve a thing, is because it can't solve it.

btw, you should know the difference between non linear and linear systems

#5 neanderix

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Posted 04 February 2007 - 04:26 PM

isn't regardless, your OS (2.20), doesnt can solve non linear systems, only OS 3.0 can do it.
When the CP ''refuses'' to solve a thing, is because it can't solve it.


I can't see a non-linear system here - and btw, if you had read my post properly, you would have found, that the Classpad didn't solve the example in the manual either.

But the problem has gone, i updated my Classpad half an hour before.

Volker

#6 The_AFX_Master

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Posted 04 February 2007 - 04:38 PM

I can't see a non-linear system here


The two examples that you gave here.. are a non-linear systems, then you don't know the difference between a linear a non linear one. in the last one, seems to be that there is a mistake on the manual ( a + or - should be instead a *, of course if it's a 2.2 manual)

{12*x*y=5, 2*x-3*y=-8}.. should be {12*x+y=5, 2*x-3*y=-8} or {12*x-y=5, 2*x-3*y=-8}

and: 1/x is non linear.. because is a polynomial of order -1 (x^-1),

#7 neanderix

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Posted 04 February 2007 - 05:11 PM

The two examples that you gave here.. are a non-linear systems,


Ofcourse you're right... -_-

in the last one, seems to be that there is a mistake on the manual ( a + or - should be instead a *, of course if it's a 2.2 manual)

{12*x*y=5, 2*x-3*y=-8}.. should be {12*x+y=5, 2*x-3*y=-8} or {12*x-y=5, 2*x-3*y=-8}


And even here you're right - there's a typo in the result - my fault.

But: regardless wether typo or not - what i wanted to say ist, that the CP just didn't want to solve even the sample.
I know it did before so is wonder what happened to it.

By the wa: a member in the german casio forum stated that his CP gives the correct result - with OS 2.20.

Volker

now running OS 3.01

#8 The_AFX_Master

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Posted 04 February 2007 - 06:56 PM

btw, if you need to solve large and complex non linear systems... you can try CPLua with LNA.. for sure is a lot faster than the built in function on the classpad :)

#9 neanderix

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Posted 04 February 2007 - 07:55 PM

btw, if you need to solve large and complex non linear systems... you can try CPLua with LNA.. for sure is a lot faster than the built in function on the classpad :)


I think i'll give it a try althoug my Classpad and my HP 49G+ are only a kind of a hobby ;)

Volker

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Posted 06 February 2007 - 03:09 AM

I can't see a non-linear system here - and btw, if you had read my post properly, you would have found, that the Classpad didn't solve the example in the manual either.

But the problem has gone, i updated my Classpad half an hour before.

Volker


How did you do it?

I bought my Classpad last week. I was very disappointed by having to pay for an OS update for a new calculator, but after mentally accepting this bad deal from Casio and being ready to pay for it, I can't find a single web site to buy it!




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