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Calculator Community => Other Calc-Related Projects and Ideas => TI Z80 => Topic started by: Freyaday on March 31, 2011, 05:19:24 pm

Title: Symbolic Expressions
Post by: Freyaday on March 31, 2011, 05:19:24 pm

I have a series of Basic programs that I made on my calc that allow me to (sort of) deal with symbolic expressions. Here's what I have so far:
Polynomial mult/divide
Fraction rationalization
Prettyprint auto-simplified quadratic solver
Root simplifier (sqrt(20) becomes 2sqrt(5), but it works for any root)
A prog that finds all rational roots of a number (and their powers)
And a bunch more (I think)
Anything else I should make?

Title: Re: Sybolic Expressions
Post by: ZippyDee on March 31, 2011, 05:31:48 pm

Complex polynomial roots ftw! :D

Title: Re: Sybolic Expressions
Post by: Runer112 on March 31, 2011, 05:32:47 pm

Indefinite derivation/integration. ;D

Title: Re: Sybolic Expressions
Post by: Freyaday on March 31, 2011, 05:53:46 pm

Problem with ndegree poly solvers is that above quartics, not all of them are solvable. I can't even find the equations to solve a quartic. In a similar vein, if I remember correcly, indefinite integrals only work for specific kinds of functions, and the math changes with each kind.

Title: Re: Sybolic Expressions
Post by: phenomist on March 31, 2011, 06:34:53 pm

Yeah, some indefinite integrals for elementary functions output nonelementary functions.

Though for a n-degree solver, perhaps use the Newton method for approximating all the roots, complex and noncomplex? :D (for n>4)

Title: Re: Sybolic Expressions
Post by: Freyaday on March 31, 2011, 07:37:55 pm

Problem is, this has to be able to do complex coefficents, otherwise there's no point. (There's an App for that)

Title: Re: Sybolic Expressions
Post by: phenomist on March 31, 2011, 07:57:02 pm

I would imagine that the process is similar, because the derivative of a polynomial is easy to compute, regardless of the coefficients.

Title: Re: Sybolic Expressions
Post by: jnesselr on March 31, 2011, 07:59:42 pm

Quote from: Runer112 on March 31, 2011, 05:32:47 pm

Indefinite derivation/integration. ;D

I would love that!  Actually, you could do that.  I might write if for KOS if we ever get a dev version, and it allows stuff to be added in like that.