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COB160
Level 1
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Solved!

Matrix product in CAS mode display error message

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Hp Prime Graphic Calculator

Hi,

Using the app " Function" in CAS mode, I'm trying to solve this system using matrix

Schermata 2017-07-03 alle 10.25.58.png

The calculator shows me an error message . Why? How can I solve this type of matrix product? Thank you, Sorry for my eng

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Jan_D
Level 6
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You could do this:

 

2017-07-04 18.49.55.jpg

 

Explanation:

I store the matrix product into variable p, which is a column matrix of size 2 by 1.

I want its element (1,1) to be p1, and element (2,1) to be p2, so I assign p1 and p2 in the ways given.

 

This gives p1=p3 and p2 rather complicated, which I simplify.

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Joe_Horn
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Leveraging off of Jan's reply, you might find it helpful to go into Shift CAS Settings and change the Simplify setting to Maximum.  That would allow the whole problem to be solved in one step:

 

-Joe-
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COB160
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Many thanks!

I have another problem: if I try to solve a definite integral such as this

FullSizeRender 2.jpg

 

It appear a message "Unable to check if the antiderivative 1/20*(taylorx26+e^(-taylorx26+t)) has singular points for definite integration in [t,0], Why? How can i solve this?

After this message, the calculator gives the ouput "e^t/20-(t+1)/20" that is not correct cause the correct solution of the definite integral sould be "1/20*(e^-(T-t)-t+T-1)", how can i fix it? thanks

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COB160
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Ok, I've learnt that in CAS mode T is not accepted as a variable, but if I change T in x, it anyway dislpays the message "unable to check if... has singular point for definite integration", why?

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Tim_Wessman
Level 8
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T is a defined variable containing a real number. All the upper variables are. This is why the cas defaults to lower case when you are typing in it. 🙂

 

That message is simply informing you as a user information the CAS has during solving. In some cases it is warning about only being valid in complex/real domains, that additional checks were not able to be performed for additional validation of results, or similar types of things.

 

Generally, unless they interest you, just ignore it.

TW

Although I work for the HP calculator group as a head developer of the HP Prime, the views and opinions I post here are my own.
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