hp40g+.book Page 2 Friday, December 9, 2005 1:03 AM

using vectors and matrices. (Vectors and matrices cannot be entered using the Equation Writer).

To open the Equation

Writer, press the soft- key on the menu bar of the HOME screen.

The illustration at the right shows an expression being written in the Equation Writer. The soft keys on the menu bar provide access to CAS functions and commands.

To leave the Equation Writer, press to return to the HOME screen. Note that expressions written in the Equation Writer (and the results of evaluating an expression) are not automatically copied to the HOME history when you leave the Equation Writer. (You can, however, manually copy them to HOME: see page 14-8).

CAS functions are described in detail in “CAS functions in the Equation Writer” on page 14-9. Chapter 15, “Equation Writer”, explains in detail how to enter an expression in the Equation Writer and contains numerous worked examples of CAS in operation.

An example

To give you an idea of how CAS works, let’s consider a simple example. Suppose you want to convert C to the form d ⋅ 5 where C is 245 – 20 and d is a whole number.

1.Open the Equation Writer by pressing the soft- key on the HOME screen.

2.Enter the expression for C.

[Hint: use the keys on the keyboard as you would if entering the

expression in HOME. Press the key twice to select the entire first term before entering the second term.]

14-2

 

 

Computer Algebra System (CAS)