This calculator is available on the Android Market with the description 'Scientific Calculator' and the name 'TechCalc'. The calculator contains 6 computing functions in one application plus a handy scientific reference facility  the following functions are included: 1) scientific calculations, 2) hex, oct & bin format calculations, 3) graphing applications 4) matrices calculations, 5) quick formulas and 6) quick converter. Each calculator function can be accessed in turn by swiping the screen or by pressing the relevant button in the menu. A default screen layout is available for each function showing all buttons on one screen and, in each case, all the functions are also available on a range of scrollable screens where the buttons are large enough for all finger types (but where the button size can also be adjusted if required)  a complete record of each calculation is stored in the calculation history, the result of which can be used in future calculations  a full range of settings allow easy customisation including the ability to switch between portrait (the default) and landscape modes  an extensive help facility is available which also includes some useful scientific reference sections  the output can be set to scroll either vertically (the default) or horizontally as preferred  the reference facility contains a full explanation of all of the options  the option to move to the SD card for 2.2+ users is also included. 
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1) Scientific Calculator mode includes:
 Output displayed in either Standard Decimal Notation (the default), Scientific Notation or Engineering Notation
 General Arithmetic Functions
 Trigonometric Functions  radians, degrees and gradients  including a hyperbolic option
 Power & Root Functions
 Logarithmic Functions
 Modulus Function
 Random Number Functions  two available, either a direct number between 0.0 and 1.0 or a random number within a specified range
 Highest Common Factor and Lowest Common Multiple
 Statistics Functions  Statistics Summary (returns the count (n), sum, product, sum of squares, minimum, maximum, median, mean, geometric mean, variance, coefficient of variation & standard deviation of a series of numbers), Bessel Functions, Beta Function, Beta Probability Density, Binomial Distribution, ChiSquared Distribution, Confidence Interval, Digamma Function, Error Function, Exponential Density, Fisher F Density, Gamma Function, Gamma Probability Density, Hypergeometric Distribution, Normal Distribution, Poisson Distribution, Student TDensity & Weibull Distribution
 20 Memory Registers
 Conversion Functions  covering conversions of all common units for distance, area, volume, weight, speed, pressure, energy, power, temperature, time, angles and data size (Figures 10~13)
 Constants  a wide range of inbuilt constants listed in 4 categories (Figures 14~15):
 Physical & Astronomical Constants  press to include into a calculation or long press for more information on the constant and its relationship to other constants
 Periodic Table  a full listing of the periodic table  press to input an element's atomic mass into a calculation or long press for more information on the chosen element
 Solar System  press to input a planet's orbit distance into a calculation or long press for more information on the chosen planet
 My Constants  add personal constants via the history  press to input into a calculation or long press to delete from the list
In addition, the calculator can be set to fractions mode for general arithmetic functions including use of parentheses, squares, cubes and their roots.
The text of every calculation is shown as it is entered and the full textual output of each calculation is stored in the calculation history (Figures 7~8). The input to the history is prefixed to show which category of numbers was used to perform the calculation i.e. 'SCI' or 'FRA' (from the main calculator screen), 'HEX', 'OCT', 'BIN' & 'DEC'. The results of the calculations stored in the history can be input into a calculation by short pressing on the relevant calculation text  the value will be converted according to the mode that the calculator is in when the history is accessed  for example, a fraction would be converted to decimals when not in fractions mode and a decimal would be converted to a fraction if in fractions mode  similarly, 'HEX', 'OCT', 'BIN' & 'DEC' results are converted depending on the current calculator mode  the history will only show records that are relevant for the particular calculator screen  for example, 'HEX', 'OCT', 'BIN' & 'DEC' results will not be shown on the Scientific or Graphing screens and viceversa  statistics, LCM & HCF calculation texts can be viewed in the history but are not available for insertion into a calculation. Very large or very small numbers (i.e. those raised to a power) are not available for insertion into a fraction or when the calculator is in graphing mode. History records can be deleted individually by long pressing on a record in the list  alternatively, all the records in the history can be deleted by pressing the 'Delete History' button. The full history, or individual records, can also copied to the clipboard if needed (note that an htmlbased text editor/viewer is needed to subsequently display the clipboard data properly). The results from individual records can also be saved to the 'My Constants' list by long pressing on a record in the History list and choosing 'Save Result to My Constants'.
In fractions mode, each fraction is entered as a sequence separated by a comma in the format whole number, numerator, denominator  once an operator is pressed, the sequence is converted to a fraction if the fraction value is less than 1, it is only necessary to enter the fraction numerator and fraction denominator separated by a comma and then press an operator  the next fraction is then entered using the same sequence followed by an operator  this is repeated until the equals operator is pressed when the whole text of the calculation, with its result, is shown in fraction format (Figures 15~18). 
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2) HEX, OCT and BIN Calculator mode includes:
 Conversion between hex, oct, bin and dec
 AND, OR, XOR, NOT, NAND, NOR & XNOR Functions
 Left Hand & Right Hand Shift Functions
 Power and Root Functions
 20 Memory Registers
3) Graphing Calculator mode includes:
 General Arithmetic Functions
 Trigonometric Functions  radians, degrees and gradients  including a hyperbolic option
 Power and Root Functions
 Logarithmic Functions
 A table of results is also available together with the graph if required (Figure 19)
A range of preferences (Figures 21~23) are available via the settings tab on the menu as follows:
 Screen Layout Selection (including button and font size is some cases)
 Screen can be kept on if required
 Full Screen Mode can be set on or off
 Choice of decimal precision from 1 up to 10 decimal places
 Choice of radians, degrees or gradients for trigonometric calculations
 Choice of the number of records to store in the calculation history  between 10 and 100 records
 Vibration mode for the calculator buttons can be set on or off  vibration intensity can also be changed
 The calculator can be changed from decimal mode to fractions mode by setting fractions mode on
 Automatic formatting in Hex, OCT & BIN mode can be turned on or off
 Alphabetical sorting of the Periodic Table constants can be turned on or off
 Alphabetical sorting of the Physical laws can be turned on or off
The Reference function (Figures 24~25) also includes sections covering names in the metric system, useful mathematical formulas (Figure 25) and a detailed listing of physical laws (Figures 27~28) containing a brief description of each law. 
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