Texas instruments TI.25X User Manual

The TI.25X Solar Calculator

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.

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]).

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The Display

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.

You can enter a maximum of eight digits in the display. Any
digit key pressed after the eighth is ignored.

–

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Scientific Notation

Key

Function

a

Example: To enter 1.2345 × 106:

1.2345 a 6 1.2345 06

` \

Removes a displayed result from scientific

notation and displays it in standard decimal

format.

mantissa

exponent

floating mantissa sign

exponent sign

In scientific notation, a number is expressed as a mantissa
multiplied by 10 raised to a power (exponent).

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 n 1 a l.

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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 E when 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:

x

¦ Exponential (y
¦ Multiplication and division
¦ Addition and subtraction

) and roots (x‡y)

3. l completes all operations.

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Basic Functions

Key

Functionp, 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%.

m n I

l

Divides the displayed number by n%.

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Key

Function

V

Calculates the square of the displayed

number.` m

Calculates the square root of the displayed

number.

G

Calculates the reciprocal (x

−

) 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 (e raised to the power of

the number).

1

Using the Memory

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

M 25.

s

Recalls and displays the number stored in

memory. Does not change or clear the

number in memory.

Example:s p 3

l

M 26.

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

M 4.

s

M 27.

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

M 15.

u

M 27.

u

M 15.

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.

Note: + clears the memory. - does not clear the
memory.

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Constant Calculations

Key

Functionm p h

Adds m to each subsequent entry.

m o hSubtracts m from each subsequent entry.

m n hMultiplies each subsequent entry by m.

m m hDivides 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.

The constant key h simplifies 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.

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.

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Angle-Unit Setting

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 D is displayed.)

45 D 45.

`

x R 0.7853982

`

x G 50.

`

x D 45.

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 ` u 90.

Before starting a trigonometric calculation, use the K key
to select the appropriate angle-unit setting (D—Degree,

R—Radian, or G—Grad).

Trigonometric Functions

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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.

D Degrees (°)—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.

D Degrees (°)
. Decimal point separator
ddddddd Fractional part of a degree

For example, enter 34.047° as 34.047.

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Converting Angle-Measurement Format

Key

Function` [DMS8DD]

Converts the displayed value from

degrees, minutes, and seconds (DMS) to

decimal degrees (DD). Enter the angle in

D.MMSSsss format. If necessary, include

leading zeros as needed to place the

digits in the proper positions. Then press

`

[DMS8DD].

`

[DD8DMS]

Converts the displayed value from

decimal degrees (DD) to degrees,

minutes, and seconds (DMS). Enter the

angle in D.ddddddd format, and then

press ` [DD8DMS].

Comments

Keystrokes

Display

DMS format

33.0708

33.0708

DD format` [DMS8DD]

33.118889

DMS format` [DD8DMS]

33.0708

The TI-25X Solar can easily convert an angle
measurement from one degree format to the other.

Example: Convert 33°7'8" in DMS format to DD format and
back to DMS format.

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Rectangular-to-Polar Conversions

Θ

Comments

Keystrokes

Display

Enter x and y

10 `  8

8.

Value of

Θ` [R8P]

38.659808

Value of r` 

12.806248

Value of

Θ` 

38.659808

Θ

Comments

Keystrokes

Display

Enter r and

Θ

5 `  30

30.

Value of y` [P8R]

2.5

Value of x` 

4.330127

Value of y` 

2.5

Pressing ` [
to polar coordinates (r,

Example: Convert the rectangular coordinates (10, 8) to
polar coordinates.

To alternate between the two converted values (r and Θ),
press `  repeatedly.

R8P] converts rectangular coordinates (x,y)

).

Polar-to-Rectangular Conversions

Pressing ` [
rectangular coordinates (x, y).

Example: Convert the polar coordinates (5, 30°) to
rectangular coordinates.

To alternate between the two converted values (x and y),
press `  repeatedly.

P8R] converts polar coordinates (r,

) to

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Statistics Functions

Key

Function

g

Enters the displayed number into the

statistics register as a data point.

`

z

Removes the displayed number from the

statistics register.

`



Calculates the mean of the entered data.

`

ƒ

Calculates the population standard deviation

of the entered data (n weighting).

`

‚

Calculates the sample standard deviation of

the entered data (n . 1 weighting).

`

ƒ

V

Calculates variance using n weighting (for

population data).

`

‚

V

Calculates variance using n . 1 weighting

(for sample data).

`

†

Calculates the sum of the entered data

points.` ‡

Calculates the sum of the squares of the

entered data points.

`

[CSR]

Clears all data from the statistics register

and the STAT indicator.

The TI-25X Solar can perform statistical analysis on one­variable data.

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Example: Analyze the following test scores. Assume that

Comments

Keystrokes

Display

Clear display-0.

Clear register

`

[CSR]

0.

1st entry

96

g

1.

2nd entry

81

g

2.

3rd entry (incorrect)

97

g

3.

3rd entry (removed)

97 ` z

2.

3rd entry (correct)

87

g

3.

4th entry

70

g

4.

Mean (class average)

` 83.5

Standard Deviation

` ƒ9.4472218

VarianceV89.25

the four students are the entire population: 96, 81, 87, 70.

Important: Remember to press ` [CSR] to clear the
statistics register and return to arithmetic calculations.

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Error Conditions

The display shows E when an error occurs or when you
attempt certain operations. Press - to clear an error
condition.

In Case of Difficulty

1. If the digits fail to appear on the display:
¦ Check to be sure that no part of the solar panel is

covered.

¦ Check the intensity of the light source. The light

may be too dim to operate the calculator.

2. Press + and try the calculation again. Review the
operating instructions to be certain the calculations
were performed properly.

3. Press +, ` 4, and r to reset the display
and prepare the calculator for use.

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TI Product and Services Information

For more information about TI products and services,
contact TI by e-mail or visit the TI calculator home page on
the world-wide web.

e-mail address: [e-mail]
internet address: http://www.ti.com/calc

Service and Warranty Information

For information about the length and terms of the warranty
or about product service, refer to the warranty statement
enclosed with this product or contact your local Texas
Instruments retailer/ distributor.

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