8-3-2

Editing Program Contents

kUsing an Existing Program to Create a New Program

Sometimes you can input a new program by using a program already in memory as a base. Simply recall the existing program, make the changes you need, and then execute it.

Example 2 To use the OCTA program (page 8-1-2) to create a program that calculates the surface area (cm2) and volume (cm3) of regular tetrahedrons when the length of one side is 7, 10, and 15 cm

Use TETRA as the file name.

AThe following are the formulas used for calculating surface area S and volume V of a regular tetrahedron for which the length of one side A is known.

2

S = 3 A2, V = –––– A3 12

Use the following key operations when inputting the program.

Length of One Side A .. !J(PRGM)4(?)aav(A)6(g)5(:)

Surface Area S ............

!x(

)d*av(A)x6(g)5(^)

Volume V .....................

!x(

)c/bc*av(A)Md

 

 

 

 

 

Compare this with the program for calculating the surface area and volume of a regular octahedron.

Length of One Side A .. !J(PRGM)4(?)aav(A)6(g)5(:)

Surface Area S ............

c*!x( )d*av(A)x6(g)5(^)

Volume V .....................

!x( )c/d*av(A)Md

 

 

 

 

As you can see, you can produce the TETRA program by making the following changes in the OCTA program.

•Deleting c*(underlined using a wavy line above)

•Changing dto bc(underlined using a solid line above)

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