Squaring the Binomial
05-22-2021, 03:54 PM
Post: #1
 MullenJohn Junior Member Posts: 47 Joined: Sep 2017
Squaring the Binomial
Help,

Using my HP Prime calculator I am try to square the binomial (12*c^4 + 0.25*a^6*c)^2.

I was expecting something like (a^2 + B^2 + c) but I am getting only a number like 2.9887...

Please tell me how to expand the binomial with just the literals.

Thanks - Cheers!
05-22-2021, 04:37 PM
Post: #2
 Joe Horn Senior Member Posts: 2,009 Joined: Dec 2013
RE: Squaring the Binomial
(05-22-2021 03:54 PM)MullenJohn Wrote:  Help,

Using my HP Prime calculator I am try to square the binomial (12*c^4 + 0.25*a^6*c)^2.

I was expecting something like (a^2 + B^2 + c) but I am getting only a number like 2.9887...

Please tell me how to expand the binomial with just the literals.

Thanks - Cheers!

Your variables might have values assigned to them. Purging them will force Prime to use them symbolically. Try purge(c) or del(c), and then try your simplification again.

Suggestion: Any time CAS sees a decimal point, it flips from "Exact" mode into "Approximate" mode. To use CAS to its full potential, avoid including any decimal points in CAS. E.g. use 1/4 instead of 0.25.

<0|ΙΈ|0>
-Joe-
05-22-2021, 05:40 PM
Post: #3
 Albert Chan Senior Member Posts: 2,703 Joined: Jul 2018
RE: Squaring the Binomial
Instead of purging variables, we can quote them. (quote(expr) == 'expr')
Quoting returns its argument unevaluated.

Cas> a:=b:=c:=1
Cas> expand('(12*c^4 + 1/4*a^6*c)^2')

1/16*a^12*c^2+6*a^6*c^5+144*c^8

---

BUG report: sometimes quoting does not work.
HP Prime emulator 2.1.14181 (2018 10 16):

Cas> expand('(12*c^4 + 1/4*a^6*c)^2')

150.0625

Not only quote not working, results somehow turned approximate.
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