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

kathrynp shared this problem 6 years ago
Answered

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.

Comments (8)

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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:

Phil279eb9e4d4bd1161624a9cec3279cdc8

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Hi,

Still Taylor Polynomials:

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

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


K.

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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

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    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.

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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

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Expand[] command

Great! Missed that one: I was trying Simplify!

K.

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This now works, thanks for the report:

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

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Thanks Murkle!

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