HP 40gs hp 40gs_user's guide_English_E_HDPMSG40E07A.pdf - Page 268

hp40g+.book Page 16 Friday, December 9, 2005 1:03 AM Note Press to obtain an intermediate result, (4- 2)(4 + 2), and again to evaluate the intermediate result. The final answer, as before, is 12. If you call a CAS function while you're writing an expression, whatever is currently selected is copied to the function's first or main argument. If nothing is selected, the cursor is placed at the appropriate location for completing the arguments. Equation Writer variables You can store objects in variables, then access an object by using the name of its variable. However, you should note the following: • Variables used in CAS cannot be used in HOME, and vice versa. • In HOME or in the program editor, use an object in a variable. to store • In CAS, use the STORE command (on the menu) to store a value in a variable. • The key displays a menu that contains all the available variables. Pressing while you are in HOME displays the names of the variables defined in HOME and in the Aplets. Pressing while you are in the Equation Writer displays the names of the variables defined in CAS (as explained on page 15-18). Predefined CAS variables • VX contains the name of the current symbolic variable. Generally, this is X, so you should not use X as the name of a numeric variable. Nor should you erase the contents of X with the UNASSIGN command (on the menu) after having done a symbolic calculation. • EPS contains the value of epsilon used in the EPSX0 command. 15-16 Equation Writer