Copyright (C) 2002 Mike Sebastian

Computing the Forensics Algorithm in Radians

Some calculators and early computers only compute trigonometric functions in radians. This can be a problem if your are wanting to produce a forensics result, since the forensics algorithm is defined in terms of degrees. However, this is not really an insurmountable problem. When the calculator or computer only computes in radians, the solution is to insert the appropriate degrees-to-radians or radians-to-degrees conversion before or after each step in the algorithm.

So, you might end up computing the forensics algorithm with a key sequence like this on a hypothetical calculator with angular conversion functions:

9
D->R
(degrees to radians, or displayed value × p ÷ 180)
SIN
D->R
COS
D->R
TAN
ARCTAN
R->D
(radians to degrees, or displayed value × 180 ÷ p)
ARCCOS
R->D
ARCSIN
R->D

Or, on a computer, you might utilize a code snippet similar to the following (all variables and functions are assumed to be of a suitable extended precision floating point type):

PI = 3.14159265358979323846264;
DR = PI/180.0; "degrees to radians"
RD = 180.0/PI; "radians to degrees"
RESULT = RD*ASIN(RD*ACOS(RD*ATAN(TAN(DR*COS(DR*SIN(DR*9.0))))));


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Last updated August 16, 2002