de0c1401-4bca-4481-ae0c-61be50425bf5 43 3 5 false false 0 decimal

&[DATE] &[TIME] - &[FILENAME]

Interactive work with Taylor() seems to be ok

x sqrt 11 Taylor 1 x + 2 /

Now, what happens when you store the same expression in a variable

T.1 x sqrt 21 Taylor :

T.1 #

lastError Assign variable.

????

Now see what is stored in \[REGION[0]]\:

T.1

This is a bug. The independent variable is replaced by the expansion point (second argument) before actually executing the diff operation.

Further observations:

x sqrt x sqrt 2 1 Taylor 2 1 sys

lastError $n$ - not defined.

x sqrt x sqrt 2 1 Taylor 2 1 sys

XY-Plot can handle the function

This doesn't throw an error but doesn't plot the tangent line

x sqrt T.1 2 1 sys x sqrt T.1 2 1 sys

...but not if stored in a variable.

Workaround: Use Maxima. The command is executed before it is stored in T.2

T.2 x sqrt x 11 taylor Maxima :

x sqrt x sqrt x 2 1 taylor Maxima T.2 3 1 sys

x sqrt x 11 taylor Maxima 1 x 1 - 2 / +

x sqrt x sqrt x 2 1 taylor Maxima T.2 3 1 sys

T.2 1 - x + 2 + 2 /