11-20-2016, 07:26 AM

Hello all, I'm new to the forum and HP calculators in general.

Working within CAS on firmware (10637), I believe that I've found some repeatable incorrect results from collect():

Numeric substitution confirms the invalid result:

I'm content with collect()'s work in the numerator but for nearly half of my uses it appears to be chewing up denominators and returning only simplified portions of them, casting doubt over the work of this function and the underlying CAS.

Perhaps I am expecting something this function wasn't designed for, but the Help appears to describe this function as returning an equivalent representation of the input, collected with respect to Var.

Thanks all

Working within CAS on firmware (10637), I believe that I've found some repeatable incorrect results from collect():

Code:

`collect((a*b+a*c)/(a*d+a*e+d*e), a)`

(a*(b+c))/(e+d)

Numeric substitution confirms the invalid result:

Code:

`subst((a*b+a*c)/(a*d+a*e+d*e), {a=2,b=3,c=4,d=5,e=6})`

269.2E-3

subst((a*(b+c))/(e+d), {a=2,b=3,c=4,d=5,e=6})

1.273E0

I'm content with collect()'s work in the numerator but for nearly half of my uses it appears to be chewing up denominators and returning only simplified portions of them, casting doubt over the work of this function and the underlying CAS.

Perhaps I am expecting something this function wasn't designed for, but the Help appears to describe this function as returning an equivalent representation of the input, collected with respect to Var.

Thanks all