\frac{1 - \tan x \cdot \tan x}{1 + \tan x \cdot \tan x}\frac{{\left(\frac{1}{1 + \tan x \cdot \tan x}\right)}^{3} - {\left(\frac{\tan x \cdot \tan x}{1 + \tan x \cdot \tan x}\right)}^{3}}{\frac{\tan x \cdot \tan x}{1 + \tan x \cdot \tan x} \cdot \left(\frac{\tan x \cdot \tan x}{1 + \tan x \cdot \tan x} + \frac{1}{1 + \tan x \cdot \tan x}\right) + \frac{1}{1 + \tan x \cdot \tan x} \cdot \frac{1}{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) (((double) (((double) pow(((double) (1.0 / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))), 3.0)) - ((double) pow(((double) (((double) (((double) tan(x)) * ((double) tan(x)))) / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))), 3.0)))) / ((double) (((double) (((double) (((double) (((double) tan(x)) * ((double) tan(x)))) / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))) * ((double) (((double) (((double) (((double) tan(x)) * ((double) tan(x)))) / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))) + ((double) (1.0 / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))))))) + ((double) (((double) (1.0 / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x)))))))) * ((double) (1.0 / ((double) (1.0 + ((double) (((double) tan(x)) * ((double) tan(x))))))))))))));
}



Bits error versus x
Results
Initial program 0.3
rmApplied div-sub0.4
rmApplied flip3--0.5
Simplified0.5
Final simplification0.5
herbie shell --seed 2020173
(FPCore (x)
:name "Trigonometry B"
:precision binary64
(/ (- 1.0 (* (tan x) (tan x))) (+ 1.0 (* (tan x) (tan x)))))