Square Root; Absolute Value; Reciprocal - Texas Instruments TI-82 Keystroke Manual

and pressing ENTER). The MATH menu will then disappear, and the calculator will display 4
Press ENTER to display the value of the expression, 64.
page 12
9

Square Root

See 3 Square Root.
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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 x
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:
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
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
− + = −
17 5 12
press ENTER to obtain the value 7.
To multiply the absolute value of −4 by the absolute value of 10,
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 4 10
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11 Reciprocal

Since the reciprocal of an integer, such as 5, may be written as
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
written by interchanging the numerator and denominator:
Another way to enter the reciprocal of a number is to use the
be explained later, the reciprocal of 4 may be written as
= − 5 +
12 . To evaluate
⋅ =
4 10 40 .
−1
key. It is denoted ABS. Thus, the keystrokes
−
7
− 17 +
5 we may not just enter
2 you would type in abs(-5)+abs(2)and
1
, it may be entered into the
5
8
, appearing as 8/5 on screen.
5
1 −
x
−
1
4 . To produce this expression on
TI-82
3
.
. On the calculator the
− 4 ⋅
10 , you could use
5
, may be
8
key. For reasons that will
9