 Graph Software for Scientists and Engineers

# 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;
}
```
\$
195.
00

RUNS ON
Windows 10,
Windows 8,
Windows 7, 2008,
Vista, XP, NT,
ME, 2003, 2000,
Windows 98, 95