CAS diff() giving incorrect results

[Albert Chan]

(09-23-2021 06:20 PM)Wes Loewer Wrote:  When I try (x^3)''(x = 4) it gives a warning and returns (6*x) = 24,

When I try same expression in the emulator, above return only 24, without warning.
I beiieve (x^3)''(x = 4) equivalent to subst((x^3)'', x = 4), only less typing.

Quote:That's an interesting notation. It appears to work for other functions as well.

If the expression is not a function, the notation may get confused with implied multiply.

XCAS> (1+x+x^2) (x=0.1)

Warning : using implicit multiplication for (1+x+x^2)(x=0.1)
x*(x^2+x+1)=(0.1*(x^2+x+1))

CAS> (1+x+x^2) (x=0.1)         → "Syntax Error"

We can get around the problem (both CAS and XCAS) with identity function.

CAS> id(1+x+x^2) (x=0.1)       → 1.11