> Abs()
I use Abs() for comparing if numbers are "reasonably" close
<CFIF abs(a - b) LT .05>
> Sgn()
I've had situations where I calculated a value and then had to decide if I
were to add or subtract that amount based on the sign of some other
variable. Rather than do
<CFIF x GT 0><CFSet a = b + c><CFElse><CFSet a = b - c></CFIF>
I've done <CFSet a = b + sgn(x) * c>
> Log()
Log can be very useful in solving equations involving exponents. Seems like
there was a CF-Talk post recently where Log was used in the solution, but I
don't remember what it was.
I've used Log() for statistical calculations like fitting a line to a series
of data points when the line was some type of curve rather than a straight
line.
> ACos()
> ASin()
> Atn() (or otherwise referred to as Atan)
> Cos()
> Sin()
> Tan()
> Pi()
I have had little reason to use trig functions or PI in business
programming. The only application I've had was zipcode distance
calculations.
<CFSET Temp = sin(Latitude1) * sin(Latitude2 * pi()/180) +
cos(Latitude1) * cos(Latitude2 * pi()/180) *
cos(Longitude2 * pi()/180 - Longitude1)>
<CFIF temp is 1>
<CFSet Mileage = 0>
<CFElse>
<CFSET Mileage = 3963.0 * (ATN(-Temp / SQR(-Temp * Temp + 1))
+ 1.570796326794895)>
<CFSet Mileage = Round(Mileage * 100) / 100>
</CFIF>
Hope this helps.
Chris
---------------------------------------------------
Christopher P. Maher
mailto:[EMAIL PROTECTED]
Maher Associates, Inc.
Actuarial and Computer Consulting
http://www.maherassociates.com
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