(1-10x)^4 does not expand
04-10-2019, 06:29 PM
Post: #1
 MullenJohn Junior Member Posts: 41 Joined: Sep 2017
(1-10x)^4 does not expand
Help, In HOME with HP Prime,

I enter (1-10x)^4 and expect something like #x^4+#x^3+#x^2+#x+c where # is any number.

However my result is (1.-10x)^4 which is just what I started with.

How do I get the binomial raised to the 4th power to expand?

Thanks - Cheers!
04-10-2019, 06:45 PM
Post: #2
 Aries Member Posts: 157 Joined: Oct 2014
RE: (1-10x)^4 does not expand
Hi,
expand is an algebric CAS command, you can use it for polynomials and rational functions (powexpand for expressions with exponents and texpand for transcendent functions)
Best,

Aries
04-10-2019, 06:59 PM
Post: #3
 MullenJohn Junior Member Posts: 41 Joined: Sep 2017
RE: (1-10x)^4 does not expand

I am still confused.

Are you saying that I cannot directly input (1-10x)^4 in the HOME textbox and get the expansion.

Are you saying I must use the powexpand command in the CAS textbox to get the expansion?

Cheers!
04-10-2019, 07:13 PM
Post: #4
 Aries Member Posts: 157 Joined: Oct 2014
RE: (1-10x)^4 does not expand
Try CAS.expand('expression') or CAS.expand('expression','variable') in HOME mode
Algebric objects need single quotes.
Best,

Aries
04-10-2019, 07:57 PM
Post: #5
 DrD Senior Member Posts: 1,132 Joined: Feb 2014
RE: (1-10x)^4 does not expand
Either of these should work:

[HOME]
CAS("expand((1-10*x)^4)");
CAS.expand("(1-10*x)^4");

Note the multiplication sign at 10*x, to avoid implicit multiplication issues.
04-10-2019, 08:26 PM
Post: #6
 MullenJohn Junior Member Posts: 41 Joined: Sep 2017
RE: (1-10x)^4 does not expand
Aries & DrD,

Thank you for replies. It is clear to me now. Cheers!
04-11-2019, 06:21 AM
Post: #7
 Aries Member Posts: 157 Joined: Oct 2014
RE: (1-10x)^4 does not expand
Dont mention it !
Best,

Aries
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