The following are the formulas for determining the surface area (S) and volume (V) of a regular octahedron when the length of one side (A) is known.

S = 2'3 A2, V = '32 A3

The following program prompts for input of A and then outputs S and V in accordance with the above programs.

"A" ?A2 × '(3) × A2^ '(2) ÷ 3 × A3

• Specify COMP as the run mode for the program, and assign the file name “OCTAHEDRON”.

Operation Procedure

1. Press N5(PROG) to enter the PROG Mode.• This displays the Program Menu screen.2. Press 1(NEW).

This displays the file name input screen, and automatically alpha-lock the calculator’s keyboard (1S).

3.Enter up to 12 characters for the file name and then press E.This registers the file name and displays the run mode selection screen.5(O)$(C)2(T)i(A))(H)c(E)s(D) /(R)5(O)4(N)E

4.Press the number key that corresponds to the mode you want to assign as the program’s run mode.

Here, press 1(COMP). This selects COMP as the run mode, and displays the program editing screen.

Important!

A run mode can be assigned only when you are creating a new program. You cannot change the run mode of a program once it has been assigned.

5.Input the program.• Here we will input the program shown below.S!(")Si(A)S!(") z3(PROG)1(?)z3(PROG)2()Si(A)E 2*!3)*Si(A)x1x(^)!2)/3*Si(A)63)• Pressing E inputs a newline symbol (_).

E-106