TI-82 9
and pressing ENTER). The MATH menu will then disappear, and the calculator will display 4
3
.
Press ENTER to display the value of the expression, 64.
page 12
9 Square Root
See 3 Square Root.
page 14
10 Absolute Value
The absolute value of a number is the number's distance from zero on the number line. The
absolute value key is the second function on the
1
key. It is denoted ABS. Thus, the keystrokes
needed to get the absolute value would be 2nd [ABS]. When we write the absolute value of −7 with
pencil and paper, we enclose the number within two vertical bars: 7− . On the calculator the
absolute value of −7 is denoted abs(-7). Produce this expression on your Home screen by first
pressing 2nd [ABS]. Then open a set of parentheses, type in −7 (being sure to use the gray negative
key), and close the parentheses. Press ENTER to find the absolute value of −7, which is 7. Try
doing this problem again, only don't use the parentheses. You will find that when you take the
absolute value of a single number, the parentheses are optional.
As was the case with square roots, the calculator only takes the absolute value of the number
immediately to the right of the abs symbol. To evaluate 517 +− we may not just enter
abs–17+5, because the calculator would do the absolute value of the −17 only. We want it to do
the absolute value of the entire expression contained within the absolute value bars. To do this, we
must put the expression inside a set of parentheses: abs(–17+5). The result is 12, since
1212517 =−=+− . To evaluate 25 +− you would type in abs(-5)+abs(2)and
press ENTER to obtain the value 7.
To multiply the absolute value of −4 by the absolute value of 10, 104 ⋅− , you could use
the multiplication key to type in abs(-4)*abs(10), or you could just put the two absolute
values side-by-side with no symbol in between: abs(-4)abs(10). The calculator still knows
you mean that these two absolute values are to be multiplied. The value of this expression is 40,
since 40104104 =⋅=⋅− .
page 21
11 Reciprocal
Since the reciprocal of an integer, such as 5, may be written as
5
1
, it may be entered into the
calculator as we would enter any fraction of this type: 1/5, using the division key ÷ to produce
the diagonal slash / on the screen. Similarly, the reciprocal of a fraction, such as
8
5
, may be
written by interchanging the numerator and denominator:
5
8
, appearing as 8/5 on screen.
Another way to enter the reciprocal of a number is to use the
1−
x key. For reasons that will
be explained later, the reciprocal of 4 may be written as
1
−
. To produce this expression on
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