[fixed] CAS: annoying feature, although not a bug!

kathrynp shared this problem 9 years ago

Hi,

Having used the TaylorPolynomial command in the Input bar, and got unsimplified coefficients, which then became ugly fractions on using the Simplify command, I was pleased to see that CAS gave me a very nice fractional display, just as I would write out 'by hand'.

However, on switching on the radio button to display the function, the algebra changed from ascending powers of x (usual display for UK, I think) to descending powers of x, which is a bit annoying and confusing for students. I can enter it twice and just display graphically once, but is there a way to avoid the change occurring?

K.

1

Hi,

descending powers of x, which is a bit annoying and confusing for students.
On the same subject, the annoying polynomial display on a Jonas (tmm) example below.

Cheers, :wink:

Phil

1

Hi,

Still Taylor Polynomials:

TaylorPolynomial[(1-3x)^(1/3),0,4]

works in Input bar (although with unsimplified coefficients), but gives ? in CAS.

K.

1

Hi,

Taylor in CAS does not currently support x^(a/b) or cbrt (https://jira.geogebra.org/b... ).

TaylorPolynomial[exp(ln(1-3x)/3),0,4]

works though.

Cheers,

Zbynek

1

TaylorPolynomial[exp(ln(1-3x)/3),0,4]

Devious! Not sure my students will think of work arounds like that, though!

Any chance of simplifying the coefficients in the algebra view, to 'nice' fractions?

Or adding a command for binomial expansion? (I can work it out for myself, or use someone else's work, but for checking answers in student work it would be so-o-o-o convenient when I am feeling lazy or tired! :confused: )

K.

1

Hi,

to get the fractions in algebra you may use Expand[] command. And the workaround above is realy just a workaround, I hope we will be able to fix that in CAS view.

Cheers,

Zbynek

1

Expand[] command

Great! Missed that one: I was trying Simplify!

K.

1

This now works, thanks for the report:

TaylorPolynomial[(1-3x)^(1/3),0,4]

1

Thanks Murkle!

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