\frac{1 - \tan x \cdot \tan x}{1 + \tan x \cdot \tan x}\log \left(e^{\frac{1 - \tan x \cdot \tan x}{1 + \tan x \cdot \tan x}}\right)double code(double x) {
return ((double) (((double) (1.0 - ((double) (((double) tan(x)) * ((double) tan(x)))))) / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x))))))));
}
double code(double x) {
return ((double) log(((double) exp(((double) (((double) (1.0 - ((double) (((double) tan(x)) * ((double) tan(x)))))) / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x))))))))))));
}



Bits error versus x
Results
Initial program 0.3
rmApplied add-log-exp0.4
Final simplification0.4
herbie shell --seed 2020123
(FPCore (x)
:name "Trigonometry B"
:precision binary64
(/ (- 1 (* (tan x) (tan x))) (+ 1 (* (tan x) (tan x)))))