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 + ([ON]) Function 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 Display You can enter a maximum of eight digits in the display. Any digit key pressed after the eighth is ignored.
Indicator 2nd D R G () STAT K M E
Meaning The displayed number is negative. The ` key has been pressed to access the second function (written above the key) of the next key pressed. Angle units are set to degrees. Angle units are set to radians. Angle units are set to grads. One or more parentheses are open. The calculator is in statistics mode. That is, the statistics register contains data. A number and operation are stored as a constant. A number other than zero is stored in memory. An error has occurred. You must press - or + to clear the error.
Scientific Notation In scientific notation, a number is expressed as a mantissa multiplied by 10 raised to a power (exponent).

mantissa exponent

floating mantissa sign

exponent sign

Key a `\
Function Example: To enter 1.6: 1.2345 a 6 1.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 n 1 a l.
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: Exponential (yx) and roots (xy) Multiplication and division Addition and subtraction
3. l completes all operations.
Basic Functions Key p, o, n, m Function 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. ij 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%.

Key V `m G Z `l b `k

Function Calculates the square of the displayed number. Calculates the square root of the displayed number. Calculates the reciprocal (x1) of the displayed number. Raises the displayed number (y) to a specified power (x). Calculates a specified root (x) of the displayed number (y). Calculates the common logarithm (base 10) of the displayed number. Calculates the common antilogarithm of the displayed number (10 raised to the power of the number). Calculates the natural logarithm (base e) of the displayed number. Calculates the natural antilogarithm of the displayed number (e raised to the power of the number).

Using the Memory The calculators 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 r Function 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. Recalls and displays the number stored in memory. Does not change or clear the number in memory. Example: s p 3 l M 26. 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. 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.
Note: + clears the memory. - does not clear the memory.
Constant Calculations 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. Key mph moh mnh mmh mZh Function Adds m to each subsequent entry. Subtracts m from each subsequent entry. Multiplies each subsequent entry by m. Divides each subsequent entry by m. 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.
Angle-Unit Setting Before starting a trigonometric calculation, use the K key to select the appropriate angle-unit setting (DDegree, RRadian, or GGrad). Key K `x Function Changes the angle-unit setting without affecting the displayed angle value. 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.
Trigonometric Functions Key W, X, Y Function Calculates the sine, cosine, or tangent of the displayed angle. Example: 90 W o 30 X l 0.1339746 Calculates arcsine, arccosine, or arctangent of the displayed value. Example: 1 ` u 90.

` u, ` v, `w

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. MM SS sss Degrees ()0 to 8 digits Decimal point separator Minutes (')must be 2 digits Seconds (")must be 2 digits Fractional part of a second

For example, enter 485'3.5" as 48.05035. Decimal Degrees DD angles are entered in D.ddddddd format. D. ddddddd Degrees () Decimal point separator Fractional part of a degree
For example, enter 34.047 as 34.047.

10.ENG

Converting Angle-Measurement Format The TI-25X Solar can easily convert an angle measurement from one degree format to the other. Key ` [DMS8DD] Function 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]. 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].

` [DD8DMS]

Example: Convert 337'8" in DMS format to DD format and back to DMS format. Comments DMS format DD format DMS format Keystrokes 33.0708 ` [DMS8DD] ` [DD8DMS] Display 33.0708 33.118889 33.0708

11.ENG

Rectangular-to-Polar Conversions Pressing ` [R8P] converts rectangular coordinates (x,y) to polar coordinates (r,). Example: Convert the rectangular coordinates (10, 8) to polar coordinates. Comments Enter x and y Value of Value of r Value of Keystrokes 10 ` 8 ` [R8P] ` ` Display 8. 38.659808 12.806248 38.659808
To alternate between the two converted values (r and ), press ` repeatedly. Polar-to-Rectangular Conversions Pressing ` [P8R] converts polar coordinates (r, ) to rectangular coordinates (x, y). Example: Convert the polar coordinates (5, 30) to rectangular coordinates. Comments Enter r and Value of y Value of x Value of y Keystrokes 5 ` 30 ` [P8R] ` ` Display 30. 2.5 4.330127 2.5
To alternate between the two converted values (x and y), press ` repeatedly.

12.ENG

Statistics Functions The TI-25X Solar can perform statistical analysis on onevariable data. Key g Function 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. ` Calculates the population standard deviation of the entered data (n weighting). ` Calculates the sample standard deviation of the entered data (n. 1 weighting). ` 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.

13.ENG

Example: Analyze the following test scores. Assume that the four students are the entire population: 96, 81, 87, 70. Comments Clear display Clear register 1st entry 2nd entry 3rd entry (incorrect) 3rd entry (removed) 3rd entry (correct) 4th entry Mean (class average) Standard Deviation Variance Keystrokes ` [CSR] 96 g 81 g 97 g 97 ` z 87 g 70 g ` ` V Display 0. 0. 1. 2. 3. 2. 3. 4. 83.5 9.4472218 89.25

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

14.ENG

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.

15.ENG

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: internet address: ti-cares@ti.com 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.

16.ENG

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