EC-4045 Student Scientific Calculator (650-0822) Operation Faxback Doc. # 31922 TURNING THE CALCULATOR ON AND OFF Press [ON/C] to turn on the calculator. If you do not press a button within about 6-8 minutes, the calculator automatically turns off. To turn it off sooner, press [OFF]. NOTE: The calculator loses any pending calculations when it turns off. However, the contents of memory are saved. CORRECTING ENTRY ERRORS If you enter an incorrect digit, you can erase it by pressing [--->]. Each time you press [--->], you erase the rightmost digit. To erase an entire entry, press [CE]. If you enter an incorrect function, you must re-enter your calculation from the beginning. CALCULATION ERRORS E appears in the lower left corner of the display if you: Perform a calculation that results in a value of 1 x 10^100 or larger. Try to divide a number by zero. Try to take the square root of a negative number. Exceed 4 levels of nested parentheses or use more than 15 pairs of parentheses. Exceed a function's calculation range. The calculator does not allow further calculations after an error. You must press [ON/C] to clear the error first. USING PARENTHESES As noted in "Algebraic Entry Method," your EC-4045 performs calculations according to the priority of the functions you enter. You can change the order in which the calculator performs calculations by enclosing parts of the entry within parentheses. The calculator performs calculations within parentheses first. USING MEMORY You can store running totals or other intermediate values in the calculator's memory. When a number is stored in the calculator's memory, M appears on the left of the display. To store a value in memory, press [x--->M] while the value shows on the display. To complete a calculation then add the value to memory, press [M+] while the value shows on the display. To recall the value from memory, press [MR]. To clear memory, press [0] [x--->M]. FUNCTION REFERENCE This section provides a brief description of all your calculator's functions. Function Description [+] Performs addition. [-] Performs subtraction. [x] Performs multiplication. [ / ] Performs division. [=] Totals all pending operations. [+/-] Changes the sign of the displayed number. [%] Performs percentage calculations. [x-M] Stores the displayed number in memory. [M+] Totals all pending operations and adds the result to memory. [MR] Recalls the value stored in memory. [ON/C] Turns on the calculator and clears all pending operations. [OFF] Turns off the calculator. All pending operations are lost, but memory is saved. [INV] Selects the functions printed above each key. [DRG] Switches between degrees, radians, and grads for trigonometric functions. [INV] [DRG>] Switches between degrees, radians, and grads for trigonometric functions and converts the displayed number between the different units. [hyp] Press before a trigonometric function to perform the hyperbolic form of the function. [INV] [arc hyp] Press before a trigonometric function to perform the arc hyperbolic form of the function. [sin] Calculates the sine of the displayed number. [INV] [sin^-1] Calculates the inverse (arc) sine of the displayed number. [Cos] Calculates the cosine of the displayed number. [Inv] [cos^-1] Calculates the inverse (arc) cosine of the displayed number. [tan] Calculates the tangent of the displayed number. [INV] [tan^-1] Calculates the inverse (arc) tangent of the displayed number. [F--->E] Changes the displayed number from floating decimal to engineering (scientific) notation. [INV] [TAB] n Sets the calculator to display values only to the nth decimal place (0-9). (INV TAB . returns the calculator to floating decimal.) [CE] Clears the last entry. (You must press [CE] before you enter any function.) [INV] [n!] Calculates the factorial of the displayed number. [INV] [STAT] Selects the statistics calculation mode. [>DEG] Converts a number entered as DD.MMSSSS (degrees, minutes, and seconds) to standard decimal notation. [INV] [-DMS] Converts a decimal number to degree- minute-second notation (DD.MMSSSS). [D] In the hexadecimal mode, enters the hex digit D. [In] Calculates the natural log base e of the displayed number. [INV] [e^x] Calculates the antilogarithm base e of the displayed number. [E] In the hexadecimal mode, enters the hex digit E. [log] Calculates the log base 10 of the displayed number. [INV] [10^x] Calculates the antilogarithm base 10 of the displayed number. [F] In the hexadecimal mode, enters the hex digit F. [a] In the standard calculation mode, recalls or enters either the radius (for a polar coordinate) or the x value (for rectangular coordinates). In the complex mode, enters the real part of a complex number. [INV] [--->r(omega)] Converts the x and y values entered with the [a] and [b] keys into polar coordinates (r and (omega)) and displays the radius. Press [b] to see the angle. [b] In the standard calculation mode recalls or enters either the angle (for a polar coordinate) or the y value (for rectangular coordinates). In the complex mode, enters the imaginary part of a complex number. [INV] [--->xy] Converts the r and 0 values entered with the [a] and [b] keys into rectangular coordinates (x and y) and displays the x coordinate. Press [b] to see the y coordinate. [--->] Erases the rightmost digit from a value you are entering. [INV] [CPLX] Selects the complex number calculation mode. [EXP] Press before entering an exponent. [INV] [pi] Enters the value for pi. [A] In the hexadecimal mode, enters the hex digit A. y [y^x] x Calculates the xth power of y. y [INV] [^x (root)y] x Calculates the xth root of y. [B] In the hexadecimal mode, enters the hex digit B. [(Square root)x] Calculates the square root of the displayed number. [INV] [^3(root) x] Calculates the cube root of the displayed number. [C] In the hexadecimal mode, enters the hex digit C. [X^2] Calculates the square of the displayed number. [INV] [I/x] Calculates the reciprocal of the displayed number. [ ( ] Opens a parenthetical expression. [INV] [x--->y] Swaps the immediate pending total with the number in the display. [ ) ] Closes a parenthetical expression. [n] In the statistical mode, recalls the number of entered date values. [INV] [sigma x] In the statistical mode, recalls the sum of the entered data values. [INV] [--->BIN] Converts the displayed number to binary mode. [INV] [--->OCT] Converts the displayed number to octal and selects the octal mode. Converts the displayed number to hexa [INV] [--->HEX] decimal and selects the hexadecimal mode. [INV] [--->DEC] Converts the displayed number to decimal and selects the decimal mode. [X^-] In the statistical mode, recalls the mean of the entered data. [INV] [sigma x^2] In the statistical mode, recalls the sum of the squares of the data. [S] In the statistical mode, recalls the sample standard deviation. [INV] [omega] In the statistical mode, recalls the population standard deviation. [DATA] In the statistical mode, enters the displayed value as a data item. [CD] In the statistical mode, clears a data entry from memory. [INV] [RND] Generates a pseudorandom three-digit number between 0.001 and 0.999. NOTE: If a close parenthesis falls at the end of an equation, you do not have to enter it. CONSTANT CALCULATIONS The constant feature lets you perform repetitive calculations without re-entering a constant value and function each time. The constant is automatically set when you perform a calculation with addition, subtraction, multiplication, division, and two-value powers or roots. PERCENTAGE CALCULATIONS Your calculator easily performs add-on and discount percentages. DEGREE/RADIANS/GRADS CONVERSIONS Your calculator performs trigonometric functions (sine, cosine, etc.) using either degrees, radians, or grads as the basic unit. Because different applications use the different basic units, the EC-4045 can convert between the different units. To select a unit, repeatedly press [DRG] until the desired unit indicator (DEG, RAD, or GRAD) appears at the top of the display. To convert between units, set the calculator to the first unit and enter the value. Then repeatedly press [INV] [DRG>] until the calculator displays the target unit. The displayed value changes to the equivalent value of the target unit. DEGREES/MINUTES/SECONDS CONVERSIONS Some calculations are easier to enter as degrees, minutes, and seconds. However, the trigonometric functions expect values to be in decimal equivalents. One minute is 1/60 of a degree, and 1 second is 1/60 of a minute. Rather than convert degrees, minutes, and seconds to a decimal number by hand, you can enter the value in the form DD.MMSSss (DD=degrees,MM=minutes, SS=seconds, ss=hundreths of a second) and then quickly convert the value to its decimal equivalent. After you perform a calculation, it is often much easier to understand the result if it is presented as degrees, minutes, and seconds, rather than as a decimal number. Your EC-4045 lets you easily convert decimal numbers to degree, minute, and second representation. POLAR/RECTANGULAR CONVERSIONS Your RC-4045 easily converts between polar and rectangular coordinates. Be sure to select the correct angular units (degrees, radians, or grads) before you begin calculations. NOTES: The values are stored and recalled using the [a] and [b] keys. You can recall the x radius value by pressing [a]. You can recall results with [a] or [b], until you enter a number, press a function key, change the calculation mode, or clear the display. You must enter [a] and [b] together. If, for example, you enter an x value and press [a], then calculate a y value by adding two numbers together, the value is no longer saved in [a]. COMPLEX NUMBER CALCULATIONS To perform complex number calculations, press [INV] [CPLX] so CPLX appears at the top of the display. To exit the complex calculation mode, select any calculation mode or press [INV] [CPLX] again so CPLX disappears. NOTE: You cannot perform memory, constant or parenthetic calculations while in the complex mode. Complex numbers are represented in the form of a + bi. To enter a complex number: 1. Enter the real part of the number. 2. Press [a]. 3. Enter the imaginary part of the number. 4. Press [b]. The calculator uses complex numbers as distances in the real and imaginary directions. Complex numbers can also be represented as magnitudes aimed at an angle (polar form). The polar form is r<(theta) where r is the magnitude and (theta) is the angle from the real axis. The units of (theta) can be degrees, radians, or grads. You can convert between both imaginary and real polar and rectangular coordinates. To convert a polar complex number to rectangular form: 1. Select the desired angle units. 2. Enter the magnitude and press [a]. 3. Enter the angle and press [b]. 4. Press [INV] [--->xy]. The real part appears. 5. Press [b] to see the imaginary part. To convert a rectangular complex number to polar form: 1. Select the desired angle units. 2. Enter the real part and press [a]. 3. Enter the imaginary part and press [b]. 4. Press [INV] [--->r(theta)]. The magnitude appears. 5. Press [b]. The angle appears. DECIMAL/HEXADECIMAL/OCTAL/BINARY CALCULATIONS AND CONVERSIONS Your EC-4045 lets you easily calculate in base 10 (decimal), base 16 (hexadecimal), base 8 (octal), and base 2 (binary). It can also convert numbers from one base to another. STATISTICAL CALCULATIONS Your EC-4045 can perform single-variable statistical calculations. To enter a series of data: 1. Press [INV] [STAT] to select the statistical mode. 2. Press [ON/C] to clear the display. 3. Enter a data value, then press [DATA]. Repeat this step for each data value. The calculator automatically calculates and stores the mean, the sum of all data values, the number of data values, the sum of the squares of all data values, the population standard deviation, and the sample standard deviation. To Recall Press Number of data values [n] The sum of all data values [INV] [(sigma)x] The mean of all data values [x/-] The sum of squares [INV] [(sigma)x^2] Sample standard deviation [S] Population standard deviation [INV] [omega] If you enter an incorrect data value, before you press [DATA], simply press [CE] then enter the correct data value and press [DATA]. If you enter an incorrect data value and then press [DATA], re-enter the value and press [INV] [CD] to remove the data value. CALCULATION RANGE Numbers you enter and all results have a range of: +/-1 x 10^-99 to +/-9.999999999 x 10^99 and 0 NOTE: When the absolute value is less than 1 x 10^-99, the calculator assumes the value is 0. For functions other than those shown in the table, the error is +/-1 at the 10th digit, as a rule. (In the scientific notation system, the error is +/-1 at the lowest digit of mantissa display). Errors are accumulated in each stage of continuous calculations, causing accuracy to deteriorate. (EB 4/15/96) (LB 3/28/96)