HP 40gs hp 40gs_user's guide_English_E_HDPMSG40E07A.pdf - Page 190

hp40g+.book Page 8 Friday, December 9, 2005 1:03 AM Send expressions from HOME to CAS history Send expressions from CAS to HOME history 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}, { 2 , 1}}) L1 then you have: TRAN(L1) = {{S2 + 1, 2 }, {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 + 2 ) 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. 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 14-8 Computer Algebra System (CAS)