\frac{1 - \tan x \cdot \tan x}{1 + \tan x \cdot \tan x}\frac{1}{\frac{1 + \tan x \cdot \tan x}{1 - \tan x \cdot \tan x}}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) (1.0 / ((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 clear-num0.4
Final simplification0.4
herbie shell --seed 2020148
(FPCore (x)
:name "Trigonometry B"
:precision binary64
(/ (- 1.0 (* (tan x) (tan x))) (+ 1.0 (* (tan x) (tan x)))))