[Request] Control of algebraic expressions CAS
06-08-2016, 01:50 PM (This post was last modified: 06-08-2016 02:33 PM by compsystems.)
Post: #3
 compsystems Senior Member Posts: 1,196 Joined: Dec 2013
RE: [Request] Control of algebraic expressions CAS
expressions rewrite alters the domains of expressions in many cases, rewrite the expressions is difficult to identify entry

fabulous if you can include a flag, so that the entries are not evaluated, at least in xcas

for example I want to know what the numerator and denominator of the following expression 'x^3/x^2', to make a symbolic derivation step as didactic project from my university, unfortunately this is evaluated as X =(

the following code will never be executed, the CAS hpprime is good, but does not allow me to do I want, with simple improvements could be the best CAS on calculators, the hp48/50 calculator retains the inputs to run obj-> that is similar to PART function (see PART FUNCTION on HP48/50) http://www.hpmuseum.org/forum/thread-6377.html)

if (operator=="/") then
Return (part2*diff_table(part1,var)-part1*diff_table(part2,var))/(part2^2);
end;

∂(x^3/x^2,x) -> ((x^2*∂(x^3,x))-(x^3*∂(x^2,x)))/x^2^2 -> 1

Code:
     // version 0.2 Jun 6 2016 by COMPSYSTEMS COPYLEFT inv(©) #cas diff_table(xpr,var):= BEGIN     LOCAL nparts, operator, part1, part2;     LOCAL xprSameVar;     //CASE 1: if the expression is a variable name or identifier     if (type(xpr)==DOM_IDENT) then         // CASE 2: if the expression is equal to the variable, example diff(x,x)=1, otherwise diff(x,y)=0         return when(xpr==var,1,0);     end;     // number of parts of the expression     nparts:=part(xpr);     //operator     operator:=part(xpr,0); if (operator=="/") then   Return (part2*diff_table(part1,var)-part1*diff_table(part2,var))/(part2^2);     end; ...
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 Messages In This Thread [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016, 11:48 AM RE: [Request] Control of algebraic expressions CAS - parisse - 06-08-2016, 12:58 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016 01:50 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-08-2016, 07:18 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016, 08:55 PM RE: [Request] Control of algebraic expressions CAS - Tim Wessman - 06-08-2016, 09:10 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016, 09:13 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016, 09:31 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-08-2016, 10:12 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-09-2016, 05:44 AM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-09-2016, 10:45 AM RE: [Request] Control of algebraic expressions CAS - parisse - 06-09-2016, 10:58 AM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-09-2016, 11:04 AM RE: [Request] Control of algebraic expressions CAS - parisse - 06-09-2016, 11:59 AM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-09-2016, 12:20 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-09-2016, 02:23 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-09-2016, 06:32 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-10-2016, 04:46 AM RE: [Request] Control of algebraic expressions CAS - parisse - 06-10-2016, 06:33 AM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-10-2016, 03:27 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-10-2016, 06:47 PM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-10-2016, 07:34 PM RE: [Request] Control of algebraic expressions CAS - parisse - 06-11-2016, 07:27 AM RE: [Request] Control of algebraic expressions CAS - compsystems - 06-23-2016, 02:03 AM RE: [Request] Control of algebraic expressions CAS - parisse - 06-23-2016, 04:26 AM

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