Last[], Dimension[] in CAS don't work properly

gno shared this problem 5 years ago
Answered

Hi,


In CAS the commands Last[], Dimension[], Take[] (with Length[]) don't work properly.

In Algebra (entering in the Input Bar) they work!

In the attached file

https://ggbm.at/569479

you find some examples.

    Last[<Matrix>]

returns -> ? in CAS.

See CAS#2, #4, #6 in the attachment.

    Dimension[<Matrix>]

returns -> ? in CAS if Matrix has only 1 row.

See CAS#12, #16


Using Length[] to get the last row with Take[]

    Take[M,Length[M],Length[M]]

does not work/returns an error.

See CAS#7, #19

But

    Take[M,Length[M]-1,Length[M]-1]

does return the row before last.

See CAS#22.


Calculating the length in advance

    L=Length[Matrix]

and then using it within Take[] works!

See CAS#7 - #10, #19 - #21


Typing Length in an empty CAS cell only offers

    Length[ <Function>, <Start x-Value>, <End x-Value> ]

    Length[ <Function>, <Start Point>, <End Point> ]

but not:

    Length[ <Object> ]

    Length[ <Curve>, <Start t-Value>, <End t-Value> ]

    Length[ <Curve>, <Start Point>, <End Point> ]

although they are accepted.


This seems to be a new feature in GeoGebra 5.0.47:

  • To be able to open the context menu of an object in Graphics View (right-click) you MUST select the object first and then right-click on it?!

In GeoGebra 5.0.42 (4.4.40+) you can immediately perform the right-click on an object in Graphics to get the context menu without having to select the object beforehand.


Gerhard

Comments (1)

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1

Thanks, all should be working now in 5.0.49.0

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