I recently bought a second-hand calculator HP 40gs and even reading the user manual, I'm having some problems.
I would like to store two matrices in this form:
[sin(theta); cos(theta), sin(theta); cos(theta)]
[cos(theta); sin(theta), cos(theta); cos(theta)]
and then make the multiplication, willing to have the result in the form of
instead of having the numbers shown.
The problem is that as soon as I fill the matrices with for example sin(T), it reads the T variable (which has not been yet defined, so it's considered =0) and in the matrix shows 0, instead of sin(T) literally typed.
You have to use the "CAS" button and 2D editing screen. That is the only place in the calculator that does not automatically evaluate variables (A-Z and Theta ARE predefined as 0 unless you have stored something in there). Are you doing things in teh CAS screen?
Although I work for the HP calculator group as a head developer of the HP Prime, the views and opinions I post here are my own.