97ceae7c-dc38-4574-a7d1-be9893d9bf3d 6 4 5 false false 0 decimal

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Solve the equation:

a x 2^9 - x Solve (: 9 - x 2^+ x Solve

a x 3 - ≡ x 3 ≡ 21 sys

I wanted to convert the system in an array to use in the for-loop, like the following:

a sys2mat.1 x 3 - ≡ x 3 ≡ 21 mat

But when I am trying to assign to a variable, it does not work:

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aa a sys2mat.1 : 9 - x 2^+ x Solve

aa x 3 - ≡ x 3 ≡ 21 sys

1) Method to convert all the solutions

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u 0 : sol a sys2mat.1 u u 1 + : x Clear all_solutions u el sol Assign : 31 line for 21 line

OK all_solutions 3 - 321 mat

2) Method to filter the solutions the meet the criteria

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filter the positive solution sol a sys2mat.1 u u 1 + : x Clear s.pos sol Assign : s.pos 0 > break none if 41 line for

OK s.pos 3

shouldn't x be defined since the break happens after the assignmet? x x

Filter the negative solution sol a sys2mat.1 u u 1 + : x Clear s.neg sol Assign : s.neg 0 < break none if 41 line for

OK s.neg 3 -

shouldn't x be defined since the break happens after the assignmet? x x

3) Method to filter the solutions the meet the criteria without clearing x(not working properly)

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filter the positive solution sol a sys2mat.1 u u 1 + : s.pos sol Assign : s.pos 0 > break none if 31 line for

Since x was not cleared I think the Assign function at the second iteration tried to evaluate a boolean where both hand side where definene, resulting in false (0) s.pos 0

33 - ≡ Assign 0

x is not cleared x 3 -

lastError

Filter the negative solution sol a sys2mat.1 u u 1 + : s.neg sol Assign : s.neg 0 < break none if 31 line for

not sure why is not evaluating like the example above s.neg solve: all variables must not be numbers.
 -- an error. To debug this try: debugmode(true);
(%i30)

x 3 -

lastError Questa azione non può venire eseguita con testo.

translation: "this action cannot be performed with text"

4) Trying to be clever

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x Clear 1

x 2^1 - x 0 > 21 sys x Solve no result