Trigonometric and General Math Functions

This page provides a brief description of the functions available in the Y=f(X) command and similar commands. For a more detailed description of each function, click on the function name. Function names are not case specific.

Please note: All dates taken as input arguments to these functions are Excel 1900 date system serial numbers, the internal date format used throughout DPlot.

ABS	Absolute value
ACOS	Arccosine (inverse cosine)
ACOSH	Inverse hyperbolic cosine
ASIN	Arcsine (inverse sine)
ASINH	Inverse hyperbolic sine
ATAN	Arctangent (inverse tangent)
ATAN2	Arctangent (inverse tangent)
ATANH	Inverse hyperbolic tangent
BESSELJ	Bessel function of the first kind
BESSELY	Bessel function of the second kind
CDF	Cumulative distribution function
CEIL	Rounds a number up
COS	Cosine
COSH	Hyperbolic cosine
DATE	Excel 1900 date system serial number that represents the input year, month, and day
DAY	Day of the month from a date (1-31)
ERF	Error function
ERFC	Complementary error function
EXP	Exponent (inverse of log)
FACT	Factorial
FLOOR	Rounds a number down
FPOWER	Raises a number to a fractional power
GCD	Greatest common divisor
LCM	Least common multiple
LOG	Natural (base-e) logarithm
LOG10	Base-10 logarithm
MAX	Maximum of two values
MIN	Minimum of two values
MOD	Remainder after division
MONTH	Month from a date (1=January)
MROUND	Returns a number rounded to the desired multiple
NORMDIST	Normal distribution
NORMDISTCDF	Cumulative distribution function (integral of NORMDIST)
NORMINV	Inverse of NORMDISTCDF
NORMRAND	Normally-distributed random number
PMT	Calculates loan payments
RANDBETWEEN	Uniformly-distributed random number between specified limits
RND	Random whole number
ROUND	Rounds a number to a specified number of digits
SIGN	Sign of a number
SIN	Sine
SINH	Hyperbolic sine
SQRT	Positive square root
SUM	Add result of argument to previous result. Useful for Taylor series.
TAN	Tangent
TANH	Hyperbolic tangent
WEEKDAY	Day of the week from a date (1=Sunday, 7=Saturday)
WEEKNUM	Number of weeks since start of year for a given date
YEAR	Year from a date

Excel date system

DPlot uses Microsoft Excel for Windows 1900 Date System serial numbers for date values, with one exception: Excel limits date input to January 1, 1900 through December 31, 2078. DPlot allows dates between October 15, 1582 and December 31, 9999.

In this system a serial number of 1 corresponds to January 1, 1900. The following code converts a month, day, and year to the Excel 1900 Date System serial number for years between 1900 and 2099, inclusive.

if( Year >= 1900 && Year <= 2099 )
{
    if( Month > 2 )
        SerNum=floor(365.25*Year)+floor(30.6001*(Month+1))+Day-694037;
    else
        SerNum=floor(365.25*(Year-1))+floor(30.6001*(Month+13))+Day-694037;
}

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