PART I: Computations
1. Turn [ON]. Off: [2nd] [OFF] or just wait about
4 minutes. It turns itself off! Darken/lighten screen: Press [2nd].
Then press and hold the [↑] or [↓] until the screen lightens or darkens
to your preference.
2. When calculator is turned on, press [CLEAR] or [2nd ]
[QUIT] to clear the screen of whatever may be on the screen when you turn
it on.
3. a) Direct functions—on the buttons in
black or white letters.
b) Indirect functions—above
the button in color, coded to match the [2nd] button.
Use [2nd] to
access.
c) [ALPHA]—another color
coded button, lets you to type in uppercase letters,
[2nd]
[alpha] type words in lower case letters,
[ALPHA] [ALPHA] allows
you to stay in alpha mode for more than one letter.
d) Menu functions—some
functions have entire menus that are accessed using
drop-down menus.
Press the [MATH]
button for example:
You can access each of the
numbered items in this menu by either typing the number itself or by using
the down arrow key to scroll down to that function. Notice that there is
an arrow after the 7. This arrow indicates that there are additional
options below this (a total of 10 functions) that can be accessed by
scrolling up or down.
Notice also that there are
additional sub-functions within this menu:
MATH NUM CPX PRB
Press the right arrow, and
the cursor now on the MATH function moves to the NUM function. Press the
right arrow again, and again, and it moves to CPX and PRB giving you the
options shown below:
4. a) Raising to a power. 25
: [2] [^] [5] [ENTER] Ans = 32.
b) Squaring numbers. 52
: [5] [^] [2] [ENTER] Ans = 25.
or [5] [x2]
[ENTER] Ans = 25.
5. Square root. – Need for parentheses!!
a)
: [2nd] [
] [25] [ )] [ENTER] Ans = 5.
b)
: [2nd] [] [1000000] [ )] [ENTER] Ans = 1000
Notice that when you pressed the square root symbol, the
square root symbol comes with an automatic open parenthesis. It will be a
very good habit to close the parentheses after you type the radicand (the
number inside the radical!). In simple problems, it won’t matter, since
the calculator automatically closes parentheses at the end of the
problem. However, if additional steps follow the square root, if YOU
don’t close the parenthesis, it could be a serious problem for you. Try
the following example:
c) 
[2nd] [ ] [25] [ )] [+] [2nd] [ ] [16] [ )]
[ENTER]
Ans = 9.
d) Just for fun, try calculating part a) and c) above,
without closing the parentheses. What you will find is that in 5a) the
closed parenthesis is not needed, but in 5c) you end up with the wrong
answer. The answer you get is equivalent to
.
6. Difference between negative [(-)] and
minus [—].
Negative [(-)] is like an
adjective. Minus [—] is like a verb.
Calculate: 6 — 3 and compare to 6 (-)
3. The first answer is 3 (subtraction!).
Now, type 6 (-) 3. It
results in an error message:
since the TI84 thinks you
probably didn’t really mean “negative”. To correct the “error,” press
the down arrow to [2: Goto] and press [ENTER]. The cursor goes directly
to the [(-)] sign. To correct the error, type [—], which replaces the
[(-)], and press
[ENTER].
Ans = 3
7.
Cube root, fourth root, fifth root, etc. To take a cube root, you
begin with [MATH] [
], [ENTER] followed by the radicand to be calculated.
Notice that, as with the square root symbol
, an open parenthesis is included with the cube root
symbol. As with the square root, it will be a very good habit to close
the parentheses after you type the radicand. Whereas with the cube root
your first step is [MATH],. to take a fourth or higher root, you must
begin with [4] for fourth root, [5] for fifth root, etc., and then [MATH]
followed by [
] [ENTER], and then the radicand. Notice that with
, there is NO open parenthesis, so there won’t be a
closed parenthesis after the radicand.
a) 
: Press [MATH] [
] [ENTER] 125 [ )] [ENTER]
Ans 5
b)
Press [MATH] [] [ENTER] 1000000 [ )] [ENTER].
Ans: 100
c):
: Press [4] [MATH] [] [ENTER] 81 [ENTER]
Ans: 3
d)
: Press [4] [MATH] [] [ENTER] 4096 [ENTER]
Ans: 8
e)
: Press [5] [MATH] [] [ENTER] 32 [ENTER]
Ans: 2
f)
: Press [5] [MATH] [] [ENTER] 1024 [ENTER]
Ans: 4
8.
Decimals to fractions:
Enter the decimal, then [MATH] [1:►Frac]
[ENTER]. [ENTER]
a) Convert 0 .25 to a fraction: [.25] [MATH] [1: ►Frac]
[ENTER]. [ENTER]
Ans: 
b) Convert 0.1666
to a fraction: [.1666] [MATH] [1: ►Frac] [ENTER] [ENTER]
Ans: 
c) Convert 
= 0.166666666666 . . . to a fraction. Note: Be sure
to give the calculator enough 6s (in this case, at least 11 digits of [6])
to establish the pattern as an infinite, repeating decimal.
[.166666666666] [MATH] [1: ►Frac] [ENTER]. [ENTER] Ans:
d) Convert 0.16666
to a fraction:
[.16666] [MATH] [1: ►Frac]
[ENTER] [ENTER].
If a decimal results in a
denominator of 5 or more digits, the calculator cannot express the result
as a fraction, and the calculator gives the answer as the decimal value.
Ans: 0.16666
e) Convert 
= 0.181818181818 . . . to a fraction. Note: In this
case, at least 6 repetitions of the [18] pattern establishes the repeating
decimal.
[.181818181818] [MATH] [►Frac] [ENTER]. [ENTER] Ans:
f) Convert 0.1818181818 to a fraction (only 5
repetitions!): Note: In this case, since there are not enough
repetitions to establish the repeating decimal, the calculator cannot
convert to a fraction, and it gives Ans:
0.1818181818
9. Need for parentheses. There are many occasions in which
parentheses are needed in order to establish the correct order of
operations. For example,
. The answer is obviously
, which is 10. However, if you use the calculator
entering 12 times 5 divided by 3 times 2, the result is 40. Obviously,
this is not what you really meant to do! The intended order of operations
can be established by placing parentheses around the numerator and
denominator.
[(] [12] [x] [5] [ )] [÷]
[(] [3] [x] [2] [ )] [ENTER] Ans: 10
10. Scientific notation.
a) Multiply 4,000,000 times
2,000,000. Ans:
8E12
Interpretation: The answer 8,000,000,000,000 is
too large to display on the calculator screen. Therefore, the calculator
automatically converts to scientific notation
which the calculator prints as 8E12. Notice that, in
words, this is 4 million times 2 million. The answer is 8 trillion. Be
sure to give the final answer in the form
, not in the form 8E12.
b) Convert 4,000,000 to scientific notation.
Locate the [MODE] function at the top of the
second column.
Type [4000000] into the
calculator. Press [MODE]. (The calculator displays a screen full of
options, most of which are irrelevant at this time.)
In the top row, you should
see the words [Normal] [Sci] [Eng].
The word [Normal] should
be surrounded by a dark, flashing box.
Press
the right arrow key once, and the dark flashing box moves to [Sci].
Press
[ENTER] to lock it into scientific notation mode.
Press
[CLEAR] to return the calculator to the previous calculation.
Press [ENTER], and the
calculator gives the previous answer in scientific notation.
Ans: 4E6 which means
c) Calculate 4 times 3. Ans:
1.2E1, which means 12.
You probably now realize that the calculator is still in
scientific notation mode, and it will remain in this mode until you change
it back to [Normal] mode. Obviously, for ordinary computations, you need
to change it back!
d)
To return to [Normal] mode, press [MODE] [Left arrow][ENTER]
[CLEAR] (The calculator returns to previous calculation.)
[ENTER]
Ans: 12
[EE] Button—Entering
scientific notation into the calculator.
e) Calculate 
using the [2nd] [EE] button (located above
the [7] button!).
Type [8] [2nd] [EE] [15] [÷]
[4] [2nd] [EE] [3] [ENTER] Ans: 2E12 or
.
Notice that parentheses were not needed, since the numerator
and denominator were entered as single numbers 8E15 and 4E3 respectively.
Also notice that this one could easily have been done without
a calculator: 8 ÷ 4 = 2 and
subtract the exponents 15 - 3 = 12. Final answer:
.
f) Calculate 
.
Notice that the denominator exponent is a “negative” (not a
“minus”) 8.
Again notice that parentheses are not needed.
Type [6.25] [2nd] [EE] [12] [÷]
[8.40] [2nd] [EE] [(-)] [8] [ENTER]
Ans: 7.44047619E19, which
should be written 
.
g) Calculate 
.
In this example, the numerator and denominator contain more
than one number, so play it safe and use parentheses around the entire
numerator and parentheses around the entire denominator.
Type: [(] [9.24] [2nd]
[EE] [9] [x] [2.03] [2nd] [EE] [(-)] [3]
[)]
[÷]
[(] [5.75] [2nd] [EE]
[(-)] [8] [x] [6.42] [2nd] [EE] [9]
[)] [ENTER]
Ans:
50811.8651.
However, the answer cannot
be more accurate than the numbers that were used to compute that answer!
Since the numbers used in the calculation are only accurate to three
digits (three significant figures!), this means that the answer is only
accurate to three digits. All the rest of the numbers in that answer
represent false accuracy. The final answer should be rounded off using
only the first three digits. Final Ans:
50,800.
11. Typing Shortcuts/Correcting Errors: [2nd]
[ANS]; [2nd] [ENTRY]; [2nd] [INS]
After a calculation has
been made, sometimes it is convenient to use this answer in the next
calculation. Sometimes it is helpful to be able to re-enter the previous
calculator entry, make changes, and recalculate. These can be
accomplished using [2nd] [ANS] (above the [(-)] key) and [2nd]
[ENTRY] (above the [ENTER] key). The following examples illustrate these
calculation shortcuts.
a) Calculate 
Keystrokes: [(] [6.3] [+] [3.2] [)] [^] [7] [ENTER]
Ans: 6983372.961
Accurate ONLY to two significant figures:
Final answer: 7,000,000
b) Suppose you discover that the previous problem should have been
. Calculate this, without retyping the entire problem.
Begin with [2nd] [ENTRY].
The calculator redisplays
the previous problem, allowing you to use the left and right arrow keys to
move the cursor. Using the left arrow key, move the cursor to the left,
over the 6, and type the desired [8], which replaces the 6. Press [ENTER]
.
New Ans:
26600198.8
Rounded to two significant figures:
Final answer: 27,000,000
Perhaps you have noticed
that the calculator makes corrections in a “strike-over” mode. That is,
when you make a correction, it strikes over what was already there.
Sometimes it is better to be able to insert characters instead of typing
over them. This can be done using [2nd] [INS] (at the top of
the third column). Consider the next example.
c) Suppose you wish to change the previous calculation from
to 
. Calculate this, without retyping the entire problem.
Begin with [2nd]
[ENTRY], use the left arrow to move the cursor back to the 3. Now, since
you need to insert an extra digit (instead of just replacing a digit),
press [2nd] [INS]. Notice that the cursor changes from a
“black box” to an “underline.” You are now prepared to “INSert” the
digits of 2 and 5. Then, with the cursor under the 3, press the [DEL]
(delete) key. Next, press the right arrow until the cursor is over the 2
in the 3.2. Press [2nd] [INS] [2], and the calculator inserts
a 2 for you. Now, press [ENTER], and you should have this answer:
Ans: 26118241.02
Rounded to three significant figures:
Final answer: 26,100,000
d) Calculate the two values of
, and round to the nearest hundredth.
This actually means the two values: 
and 
Keystrokes for :
[4] [2nd] [
] [3] [ )] [+] [2] [2nd] [] [6] [ )] [ENTER]
(Note: Remember to close the parentheses after
the 3!) Ans: 11.83
Keystrokes for
:
[2nd]
[ENTRY], left arrow cursor over the +, [—] [ENTER] Ans: 2.03
Sometimes when you make an error, the
calculator catches it for you.
e)
Suppose you are trying to calculate
(see #10f) and in the process of entering the
calculations, you enter a [—] instead of a [(-)].
Try it as follows.
[6.25] [2nd] [EE] [12] [÷]
[8.40] [2nd] [EE] [—] [8] [ENTER]
The calculator returns with the following message:
Now, you have two
choices. You can select [1: QUIT] [ENTER]! Or, you can select [2: Goto]
[ENTER] to allow the calculator to show you where the error is.
The calculator “goes to”
the error, which is the [—]. To correct the error, simply replace the
[—], with a [(-)], press [ENTER], and the calculator gives the answer as
before. Ans: 7.44047619E19, which should be written
.
Return to Part
1: Calculations
Return to Part 2: Graphing
Return to Part 3: Exercises and Answers
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