HP 50g  collect by powers of x  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: HP 50g  collect by powers of x (/thread239200.html) 
HP 50g  collect by powers of x  Juraj O.  02172013 Is there an easy way to collect terms by powers of a variable in an expression? Ie. I have an expression on the stack that looks like this A*x^2 + A*x + B*x + C I want to group (something like GROUP(expression,'x') ) it by powers of x, so that it looks like this: Ax^2 + (A+B)x + C and not something like A(x^2 + x) + Bx + C which FACTOR/SIMPLIFY/COLLECT often give me. It would also be handy if I could extract a vector of coefficients from that expression: [A A+B C].
If anyone knows how to do this please help me out :)
Re: HP 50g  collect by powers of x  Juraj O.  02172013 I think I've found what I was looking for  the function A>P from the Polynomial library by Steen S. Schmidt.
Re: HP 50g  collect by powers of x  Ronald Williams  02172013 For A*X^2 + A*X + B*x + C try using COLLECT alone and you should get A*X^2 + (B+C)*X + C as desired.
Re: HP 50g  collect by powers of x  Mike Morrow  02172013 Quote:
That would be quite remarkable!
Re: HP 50g  collect by powers of x  Ronald Williams  02172013 I'm using a real HP50g with rom 2.15 and flag settings as follows: Re: HP 50g  collect by powers of x  Mike Morrow  02172013 I doubt that any HP 50G will indicate that A*X^2 + A*X + B*X + C = A*X^2 + (B+C)*X + C
as your message number 3 in this thread proposes. :) Edited: 17 Feb 2013, 4:38 p.m.
Re: HP 50g  collect by powers of x  Gerson W. Barbosa  02172013 He was talking about the typo: A*X^2 + (B+C)*X + C instead of A*X^2 + (A+B)*X + C.
Re: HP 50g  collect by powers of x  Ronald Williams  02172013 Good catch! Thank you Gerson I did miss type the expression. As you correctly pointed out it should have been A*X^2 + (A+B)*X + C and Mike I missed your subtle humor in post #4.
Re: HP 50g  collect by powers of x  Juraj O.  02172013 I was wondering one more minor thing which doesn't really deserve its own thread. Is it possible in the equation editor, with an expression already entered, to add a factor or a summand on the beginning, from the left?
Ie. we have b•c. Is it possible to multiply it by a from the left, so we have a•b•c? Same question for b+c, so we get a+b+c?
Re: HP 50g  collect by powers of x  C.Ret  02182013 Hi, On my HP28S, 'A*x^2 + A*x + B*x + C' x 2 TAYLR returns 'C + (A+B)*x + A*2/2*x^2' then a simple COLCT leads to '(A+B)*x + A*x^2 + C' Is that expression close enough to the expected format?
Edited: 18 Feb 2013, 5:11 a.m.
