ANSWER[row] as synonymous of $row cmd

Jaime shared this idea 6 years ago

Declined

Idea, please GG TEAM add the ANSWER[row] command as synonymous with the $row command to make the instruction sequences in the CAS view more understandable for the students.

The following sequence of statements, show step by step the solution of a simple list of equations.

with $ cmd

{ y = x^2, y = 2*x + 3 } → { y = x^2, y = 2*x + 3 }
Substitute[Element[$1,2],Element[$1,1]] → x^(2) = (2 * x) + 3
$2 - (2x + 3) → x^(2) - (2 * x) - 3 = 0
Factor[LeftSide[$3]] → ((x - 3) * (x + 1))
{Element[$4,1] = 0, Element[$4,2] = 0} → {x - 3 = 0, x + 1 = 0}
{Element[$5,1] + 3, Element[$5,2] - 1} → {x = 3, x = (-1)}
Substitute[Element[$1,1],Element[$6,1]] → y=9
Substitute[Element[$1,2],Element[$6,1]] → y=9
Substitute[Element[$1,1],{$8, Element[$6,1]}] → 9=9
LeftSide[$9] ≟ RightSide[$9] -> true

with ANSWER CMD

{ y = x^2, y = 2*x + 3 } → { y = x^2, y = 2*x + 3 }
Substitute[Element[answer[1],2],Element[answer(1),1]] → x^(2) = (2 * x) + 3
answer[2] - (2x + 3) → x^(2) - (2 * x) - 3 = 0
Factor[LeftSide[answer[3]]] → ((x - 3) * (x + 1))
{Element[answer[4],1] = 0, Element[answer[4],2] = 0} → {x - 3 = 0, x + 1 = 0}
{Element[answer[5],1] + 3, Element[answer[5],2] - 1} → {x = 3, x = (-1)}
Substitute[Element[answer[1],1],Element[answer[6],1]] → y=9
Substitute[Element[answer[1],2],Element[answer[6],1]] → y=9
Substitute[Element[answer[1],1],{answer[8], Element[answer[6],1]}] → 9=9
LeftSide[answer[9]] ≟ RightSide[answer[9]] → true

Syntax in XCAS

[ y = x^2, y = 2*x + 3 ] returns [ y = x^2, y = 2*x + 3 ]
subst((ans(-1)(2)),ans(-1)(1)) returns x^2=(2*x+3)
ans(-1) - (2*x + 3) returns x^2-2*x-3=0
factor(ans(-1)) returns (x-3)*(x+1)=0
[ part(left(ans(-1)),1)=0, part(left(ans(-1)),2)=0 ] returns [x-3=0,x+1=0]
ans(-1)(1)+3, ans(-1)(2)-1 ] returns [x=3,x=-1]
subst(y=x^2,ans(-1)(1)) returns y=9
subst(y=2*x + 3,ans(-2)(1)) returns y=9
subst(y=2*x + 3,[ans(-3)(1),ans(-1)]) returns 9=9
evalb(ans(-1)) returns 1 (true)

I like this idea

Comments (4)

Michael Borcherds ● 6 years ago

Why do you think that's clearer?

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Jaime ● 6 years ago

Sorry for my bad English

Now I'm starting with GG and in my presentations in the classroom, students tell me that the $ symbol is not very natural in functional algebraic syntax

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Michael Borcherds ● 6 years ago

OK, see if they get used to it soon :)

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Jaime ● 6 years ago

We (Teacher, students) really do not like the $ command as a call to a position in a history stack., it's not natural notation about calculators (ti-nspire [cx cas] family , hp-prime cas, etc. [Portable device and computer software])

I'm going to create several CAS type scripts that will soon share them, but I insist that there should be a synonym for the $ command, I think that there is no need to make any big changes in the interpretation of expressions. But the idea is not to use CAS proprietary $$ [MATLAB (SYM TOOLBOX), MATHEMATICA, etc] software, to switch to free software as the GG calculator, xCAS

As an extra suggestion, accept a second parameter to compact the sentence

I propose that the ans command can accept an optional second argument, extract the x element from the previous list of objects

current

{ y = x^2, y = 2*x + 3 } → { y = x^2, y = 2*x + 3 }
Substitute[Element[$1,2],Element[$1,1]] → x^(2) = (2 * x) + 3

In a future GG update (As a Optional notation)

{ y = x^2, y = 2*x + 3 } → { y = x^2, y = 2*x + 3 }
Substitute[ answer[1,2], [answer[1,2] ] → x^(2) = (2 * x) + 3

Thanks

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