Lesson
#9
Functions
In this Lesson you will learn how to use certain functions to reduce the number
of
program lines that would be required to carry out frequently encountered tasks.
Experiment
#1
Calculating Square Root
This experiment will show you how to compute the square root
of
a number using the
built-in function capabilities
of
your Computer.
To obtain the square root
of
a number, simply type:
PRINT
SQR(n)
(ENTER)
where n can be any positive number. For example to find the square root
of
4,
type:
PRINT
SQR(4)
(ENTER)
which will print the correct result:
2
Now print the square root
of
2 by entering
,
PRINT
SQR(2)
and observe the correct result
1.414213562373
Finally, try to print the square root
of
the negative number
-4
by
entering
PRINT
SQR(-4)
and obtain the error message:
?FC Error
The error message indicates a "Function
Call"
error which occured because the
Computer cannot find the square root
of
negative numbers.
The square root function SQR(x) returns a numerical value for a specified numerical
"argument"
x enclosed within the parentheses. The argument must be non-negative,
but can be a constant, variable
or
expression. For example, enter the following
A = 3 : 6 = 4 : PRINT SQR(A*A +
6*6)
to compute the length
of
the diagonal
of
a rectangle whose sides are
of
length 3 and 4.
The correct length is printed
as
5
as seen in the illustration below:
111
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