HP 40gs, User Manual

Page: 190 / 444

14-8 Computer Algebra System (CAS)
Symbolic matrices are stored as a list of lists and therefore
must be stored in L0, L1…L9 (whereas numeric matrices
are stored in M0, M1,…M9). CAS linear algebra
instructions accept lists of lists as input.
For example, if you type in HOME:
XQ({{S2 + 1, 1}, { , 1}}) L1
then you have:
TRAN(L1) = {{S2 + 1, }, {1, 1}}
Some numeric linear algebra commands do not directly
work on a list of lists, but will do so after a conversion by
AXL. For example, if you enter:
DET(AXL(L1)) E1
you get:
S2–(–1 + )
Send expressions
from HOME to CAS
history
In the HOME screen, you can use the PUSH command to
send expressions to CAS history. For example, if you
enter PUSH(S1+1), S1+1 is written to CAS history.
Send expressions
from CAS to HOME
history
In the HOME screen, you can use the POP command to
retrieve the last expression written to CAS history. For
example, if S1+1 is the last expression written to CAS
history and you enter POP in the HOME screen, S1+1 is
written to the HOME screen history (and S1+1 is removed
from CAS history).
Online Help
When you are working with
the Equation Writer, you can
display online help about
any CAS command. To
display the contents of the
online help, press
2.
Press to navigate to the
command you want help
with and then press
.
You can also get CAS help
from the HOME screen. Type
2
2
2
hp40g+.book Page 8 Friday, December 9, 2005 1:03 AM