Texas Instruments -25X Solar User manual

1.ENG
The TI.25X Solar Calculator
The TI-25X Solar calculator offers you a wide range of
mathematical and statistical capabilities. This manual
explains these capabilities.
Basic Operations
To turn the calculator on, expose the solar panel to
adequate light and press +([ON]).
Key
Function
+
([ON])
If the calculator is off, turns the unit on,
clears the display, and resets angle units to
degrees.
-
When pressed once during a calculation
(but before an operation key), clears the
displayed entry and any error condition (E).
You can make a new entry and continue
with your calculation.
Pressing
-
does not clear the memory,
statistics register, or angle-unit setting.
`
Instructs the calculator to perform the
second function (written above the key) of
the next key pressed.

2.ENG
The Display
You can enter a maximum of eight digits in the display. Any
digit key pressed after the eighth is ignored.
Indicator
Meaning
–
The displayed number is negative.
2nd
The
`
key has been pressed to access
the second function (written above the key)
of the next key pressed.
D
Angle units are set to degrees.
R
Angle units are set to radians.
G
Angle units are set to grads.
( )
One or more parentheses are open.
STAT
The calculator is in statistics mode. That is,
the statistics register contains data.
K
A number and operation are stored as a
constant.
M
A number other than zero is stored in
memory.
E
An error has occurred. You must press
-
or
+
to clear the error.

3.ENG
Scientific Notation
In scientific notation, a number is expressed as a mantissa
multiplied by 10 raised to a power (exponent).
Key
Function
a
Example: To enter 1.2345 × 10
6
:
1.2345
a
6 1.2345 06
`
\
Removes a displayed result from scientific
notation and displays it in standard decimal
format.
Entering a Number in Scientific Notation
1. Enter the mantissa. If it is negative, press @.
2. Press a. Two zeros appear on the right side of the
display.
3. Enter the exponent (one or two digits). If it is negative,
press @. If you press an incorrect digit key, just
reenter the correct digits.
Converting a Number to Scientific Notation
To convert a displayed number from standard display
format to scientific notation, press n1 al.
mantissa
exponent
floating mantissa sign
exponent sign

4.ENG
Correcting Entry Errors
At any point in a calculation, you can press -twice to
clear all calculations, including any errors, and start over.
Clearing an Error Condition
The display shows Ewhen an error, overflow, or underflow
occurs or when you enter an improper operation. No entry
from the keyboard is accepted until you press -, which
clears the error condition and all pending operations.
Order of Calculations
The Algebraic Operating System (AOS™) of the TI-25X
Solar completes operations in the order of priority listed
below.
1. Single-variable functions (trigonometric, logarithmic,
square, square root, factorial, percent, reciprocal, angle
conversion, and change sign).
2. Two-variable functions:
¦Exponential (yx)and roots (x‡y)
¦Multiplication and division
¦Addition and subtraction
3. lcompletes all operations.

5.ENG
Basic Functions
Key
Function
p
,
o
,
n
,
m
Perform addition, subtraction, multiplication,
and division.
Example: 12
n
5
p
60
l
120.
l
Completes all pending operations.
Example: 4
n
5
p
9
l
29.
@
Changes the sign (positive or negative) of
the displayed number.
Example: 8
@
p
12
l
4.
i
j
Operations enclosed in parentheses are
given priority over operations outside the
parentheses. You can enter up to 15 levels
of parentheses.
l
closes any open
parenthetical expressions.
Example: 12
n
i
5
p
6
l
132.
`
{
Enters the value of p.
E
Calculates the factorial of the displayed
number.
Example: 5
E
120.
I
Converts the displayed number from a
percentage to a decimal.
Example: 25
I
0.25
p
n
I
l
Adds n% to the displayed number.
o
n
I
l
Subtracts n% from the displayed number.
n
n
I
l
Multiplies the displayed number by n%.
mn
I
l
Divides the displayed number by n%.

6.ENG
Key
Function
V
Calculates the square of the displayed
number.
`
m
Calculates the square root of the displayed
number.
G
Calculates the reciprocal (x
−
1
) of the
displayed number.
Z
Raises the displayed number (y) to a
specified power (x).
`
l
Calculates a specified root (x) of the
displayed number (y).
b
Calculates the common logarithm (base 10)
of the displayed number.
`
k
Calculates the common antilogarithm of the
displayed number (10 raised to the power of
the number).
c
Calculates the natural logarithm (base e) of
the displayed number.
`
j
Calculates the natural antilogarithm of the
displayed number (eraised to the power of
the number).

7.ENG
Using the Memory
The calculator’s memory can store data as long as the
calculator is on. You can store a number in memory for
repeated use in a calculation or to keep a running total.
Key
Function
r
Stores the displayed number in memory,
replacing any previously stored number. To
clear the memory, press
r
when zero is
displayed.
Example: 23
r
p
2
l
M25.
s
Recalls and displays the number stored in
memory. Does not change or clear the
number in memory.
Example:
s
p
3
l
M26.
t
Adds the displayed number to the current
number in memory. Does not affect the
displayed number or any calculation in
progress.
Example: 4
t
M4.
s
M27.
u
Swaps the number in memory with the
displayed number. The displayed number is
stored, and the previously stored number is
displayed.
Example: 3
n
5
l
M15.
u
M27.
u
M15.
Note: +clears the memory. -does not clear the
memory.

8.ENG
Constant Calculations
The constant key hsimplifies repetitive calculations by
storing a number and its associated operation for repeated
use.
To enter a constant operation:
1. Key in the repetitive number (m).
2. Press the operation key you want.
3. Press h.
Key
Function
m
p
h
Adds mto each subsequent entry.
m
o
h
Subtracts mfrom each subsequent entry.
m
n
h
Multiplies each subsequent entry by m.
m
m
h
Divides each subsequent entry by m.
m
Z
h
Raises each subsequent entry to the mth
power.
m
`
l
h
Takes the mth root of each subsequent
entry.
After storing the constant, you can complete each repeated
calculation by simply entering the new number and pressing
l. To erase the constant, clear the calculator or enter any
of the above arithmetic keys.

9.ENG
Angle-Unit Setting
Before starting a trigonometric calculation, use the Kkey
to select the appropriate angle-unit setting (D—Degree,
R—Radian,or G—Grad).
Key
Function
K
Changes the angle-unit setting without
affecting the displayed angle value.
`
x
Changes the angle-unit setting and converts
the displayed angle value to its equivalent
for the new setting.
Example: Convert 45
°
. (If necessary, press
K
until Dis displayed.)
45 D45.
`
xR0.7853982
`
xG50.
`
xD45.
Trigonometric Functions
Key
Function
W
,
X
,
Y
Calculates the sine, cosine, or tangent of
the displayed angle.
Example:
90
W
o
30
X
l
0.1339746
`
u,
`
v,
`
w
Calculates arcsine, arccosine, or arctangent
of the displayed value.
Example: 1 `u90.

10.ENG
Degree Format Conversions
An angle measured in degrees, minutes, and seconds
(DMS) must be converted to decimal degrees (DD) before
you can use it in a calculation.
Degrees, Minutes, and Seconds
DMS angles are entered in D.MMSSsss format.
DDegrees (°)—0 to 8 digits
.Decimal point separator
MM Minutes (')—must be 2 digits
SS Seconds (")—must be 2 digits
sss Fractional part of a second
For example, enter 48°5'3.5" as 48.05035.
Decimal Degrees
DD angles are entered in D.ddddddd format.
DDegrees (°)
.Decimal point separator
ddddddd Fractional part of a degree
For example, enter 34.047°as 34.047.