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11-01-2015
07:12 PM

11-01-2015
07:12 PM

Symbolic Matrix Solution

Can someone guide me as to why I cannot solve a matrix symbolically?

I have attached a file, that needs to be solved in terms of q1, q2, and q3.

Thanks

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7 REPLIES 7

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11-01-2015
07:57 PM

11-01-2015
07:57 PM

Re: Symbolic Matrix Solution

Ramani Ayakannu wrote:

Can someone guide me as to why I cannot solve a matrix symbolically?

What do you mean by "solve a matrix"? You can't solve a matrix, you rather can solve an equation for a given variable.

Its unclear to me upon looking at your sheet what you are trying to do and which equation you would like to solve for which variables.

I have attached a file, that needs to be solved in terms of q1, q2, and q3.

Which equation(s) do you want to be solved and which variables should be expressed in terms of q1,2,c? (I don't see any c.3 in your sheet)

If you are after something like the following, simply leave q1,2,c undefined:

You could also use the symbolic "solve" to do the job:

WE

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11-01-2015
08:11 PM

11-01-2015
08:11 PM

Re: Symbolic Matrix Solution

Werner, thanks for responding. but, I am getting the same answer as you.

This is what I am getting

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11-01-2015
08:21 PM

11-01-2015
08:21 PM

Re: Symbolic Matrix Solution

sorry, not getting the same answer as you

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11-01-2015
08:33 PM

11-01-2015
08:33 PM

Re: Symbolic Matrix Solution

Werner, I am not sure what you are doing differently, but I am not getting the same answer as yours.

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11-02-2015
02:32 AM

11-02-2015
02:32 AM

Re: Symbolic Matrix Solution

Use the simplify operator and the standard definition, not the Boolean for defining a.

Mike

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11-02-2015
06:36 AM

11-02-2015
06:36 AM

Re: Symbolic Matrix Solution

The problem is, that you have defined q.1:=...., q.c:=...... and q.2:=..... before. Delete those definitions and it sure should work.

E.g. you had defined q.0:=a.0. So when Prime solves for q.0 it simplifies it to a.0, which is obviously not what you want.

Give it a try - move the region where you multiply the inverse matrix with the vector a right to the top of your worksheet and watch the difference.

Furthermore, as Mike already stated, you have not used the "simplify" keyword (you may chose it from the ribbom menu or you may simply manually type it in in the placeholder above the arrow). If you would have used simplify, you would have got (a0 ,a1, a2) as a result just because Prime would have used the definitions you had done before.

The attached sheet should help - I have disabled the definitions I was talking about.

Werner

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11-03-2015
03:08 PM

11-03-2015
03:08 PM

Re: Symbolic Matrix Solution

I'd prefer to proceed as follows: