EC-4045 Student Scientific Calculator (650-0822) Features Faxback Doc. # 31920 Your Radio Shack EC-4045 Student Scientific Calculator uses the latest in scientific calculator technology to bring 56 math functions to your fingertips. Its 10-digit liquid-crystal display is specially designed to provide the best readability under changing or poor lighting conditions. In addition, your EC-4045 provides these features: Folding Case - protects the calculator's display and keyboard when you are carrying it. Wide Calculation Range - allows calculations with results between 1 x +/-10^-99 and +/- 9.9999 99999 x 10^99, and 0. Advanced Math Function - including trigonometric, complex, and base-n functions. Full-Function Display - displays an 8-digit mantissa with sign and a two-digit exponent with sign. Algebraic Operation - lets you enter calculations exactly as they are written. Independent Memory - lets you store subtotals into memory and then add to or recall the memory for additional calculations. Many of your EC-4045's keys have more than one function. To use the function printed on the key, you simply press the key. To use the function printed in blue above the key, you first press [INV]. NOTES: This manual gives complete instructions on how to use your calculator's functions. However, it does not teach math. Refer to your local library for books about basic math and trigonometric functions. To open the case, slightly lift the tab while you pull the case halves apart. BASIC INFORMATION DISPLAY FORMATS Your EC-4045 switches between normal number display and scientific notation, depending on the size of the number to be displayed. The calculator displays numbers from -9,999,999,999 to -0.000000001 and from +0.000000001 to +9,999,999,999 without any special formatting. All other numbers are displayed using scientific notation. In scientific notation, a number is displayed as a base value (mantissa) times 10 raised to a power (exponent). For example, in scientific notation the number 95,000,000,000 is expressed as 9.5 x 10^10. ALGEBRAIC ENTRY METHOD Your calculator uses the algebraic method for calculator entries, which means that it follows common rules of algebra when it performs the calculations you enter. These rules assign a priority to each function. The calculator performs calculations from the highest to the lowest priority. Priority Operations 1 (Highest) Single-value functions [(square root) X], [x^2], [sin], etc.) 2 Calculations within parenthesis 3 Two-value functions ([y^x], [^x(root)y]) 4 Multiplication and division 5 (Lowest) Addition and subtraction In some cases, these rules might cause you to get a result other than what you expect. For example, you know that the square of a negative number is always positive. However, if you enter [-] [3] [x^2] [=], the calculator displays: [DEG] -9. This happens because [x^2] has a higher priority than [-]. Rather than calculating "the square of negative of 3," you are calculating "the negative of 3 squared." To square negative 3, you need to either press [=] before you press [x^2], enclose [-] [3] within parentheses, or enter the calculation as [3] [+/-] [x^2]. CALCULATOR MODES Your calculator can be in one or more of several special modes. These modes are shown by special indicators on the display. This table summarizes each mode and indicates how you select it. Indicator Meaning M A value is stored in memory. E A calculation overflow has occurred. STAT The calculator is in the statistics mode. ([INV] [STAT]). INV You pressed [INV]. HYP You pressed [hyp]. DEG The calculator is in the radians mode for trigonometric calculations. ([DRG]) RAD The calculator is in the radians mode for trigonometric calculations. ([DRG]) GRAD The calculator is in the grad mode for trigonometric calculations. ([DRG]) ( ) At least one level of parenthesis is open. ([ ( ]) BIN The calculator is set to perform binary calculations. ([INV] [--->oct]) HEX The calculator is set to perform hexadecimal calculations. ([INV] [--->HEX]) CPLX The calculator is in the complex number mode.([INV] [CPLX]) NOTES: The calculator is always in either the decimal, binary, octal, hexadecimal, complex number, or statistics mode. No special indicator appears for the decimal mode. When the calculator is in the statistics, complex number, or decimal mode, it is also in either the degrees, radians, or grad mode. (EB 4/15/96) (LB 3/28/96)