Initial program 0.5
\[\frac{2 + \left(\left(\sqrt{2} \cdot \left(\sin x - \frac{\sin y}{16}\right)\right) \cdot \left(\sin y - \frac{\sin x}{16}\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\sqrt{5} - 1}{2} \cdot \cos x\right) + \frac{3 - \sqrt{5}}{2} \cdot \cos y\right)}
\]
Applied egg-rr0.5
\[\leadsto \frac{2 + \left(\left(\sqrt{2} \cdot \left(\sin x - \frac{\sin y}{16}\right)\right) \cdot \left(\sin y - \frac{\sin x}{16}\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \color{blue}{\frac{\cos x}{0.5 \cdot \left(\sqrt{5} + 1\right)}}\right) + \frac{3 - \sqrt{5}}{2} \cdot \cos y\right)}
\]
Applied egg-rr0.4
\[\leadsto \frac{2 + \left(\left(\sqrt{2} \cdot \left(\sin x - \frac{\sin y}{16}\right)\right) \cdot \left(\sin y - \frac{\sin x}{16}\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\cos x}{0.5 \cdot \left(\sqrt{5} + 1\right)}\right) + \frac{\color{blue}{\frac{4}{3 + \sqrt{5}}}}{2} \cdot \cos y\right)}
\]
Taylor expanded in x around inf 0.4
\[\leadsto \frac{2 + \color{blue}{\left(\sqrt{2} \cdot \left(\left(\sin x - 0.0625 \cdot \sin y\right) \cdot \left(\sin y - 0.0625 \cdot \sin x\right)\right)\right)} \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\cos x}{0.5 \cdot \left(\sqrt{5} + 1\right)}\right) + \frac{\frac{4}{3 + \sqrt{5}}}{2} \cdot \cos y\right)}
\]
Simplified0.4
\[\leadsto \frac{2 + \color{blue}{\left(\mathsf{fma}\left(-0.0625, \sin y, \sin x\right) \cdot \left(\sqrt{2} \cdot \mathsf{fma}\left(-0.0625, \sin x, \sin y\right)\right)\right)} \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\cos x}{0.5 \cdot \left(\sqrt{5} + 1\right)}\right) + \frac{\frac{4}{3 + \sqrt{5}}}{2} \cdot \cos y\right)}
\]
Proof
(*.f64 (fma.f64 -1/16 (sin.f64 y) (sin.f64 x)) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (Rewrite<= fma-def_binary64 (+.f64 (*.f64 -1/16 (sin.f64 y)) (sin.f64 x))) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (+.f64 (*.f64 (Rewrite<= metadata-eval (neg.f64 1/16)) (sin.f64 y)) (sin.f64 x)) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (+.f64 (Rewrite<= distribute-lft-neg-in_binary64 (neg.f64 (*.f64 1/16 (sin.f64 y)))) (sin.f64 x)) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (Rewrite<= +-commutative_binary64 (+.f64 (sin.f64 x) (neg.f64 (*.f64 1/16 (sin.f64 y))))) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (Rewrite<= sub-neg_binary64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y)))) (*.f64 (sqrt.f64 2) (fma.f64 -1/16 (sin.f64 x) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (*.f64 (sqrt.f64 2) (Rewrite<= fma-def_binary64 (+.f64 (*.f64 -1/16 (sin.f64 x)) (sin.f64 y))))): 0 points increase in error, 0 points decrease in error
(*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (*.f64 (sqrt.f64 2) (+.f64 (*.f64 (Rewrite<= metadata-eval (neg.f64 1/16)) (sin.f64 x)) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (*.f64 (sqrt.f64 2) (+.f64 (Rewrite<= distribute-lft-neg-in_binary64 (neg.f64 (*.f64 1/16 (sin.f64 x)))) (sin.f64 y)))): 0 points increase in error, 0 points decrease in error
(*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (*.f64 (sqrt.f64 2) (Rewrite<= +-commutative_binary64 (+.f64 (sin.f64 y) (neg.f64 (*.f64 1/16 (sin.f64 x))))))): 0 points increase in error, 0 points decrease in error
(*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (*.f64 (sqrt.f64 2) (Rewrite<= sub-neg_binary64 (-.f64 (sin.f64 y) (*.f64 1/16 (sin.f64 x)))))): 0 points increase in error, 0 points decrease in error
(Rewrite<= *-commutative_binary64 (*.f64 (*.f64 (sqrt.f64 2) (-.f64 (sin.f64 y) (*.f64 1/16 (sin.f64 x)))) (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))))): 0 points increase in error, 0 points decrease in error
(Rewrite<= associate-*r*_binary64 (*.f64 (sqrt.f64 2) (*.f64 (-.f64 (sin.f64 y) (*.f64 1/16 (sin.f64 x))) (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y)))))): 32 points increase in error, 50 points decrease in error
(*.f64 (sqrt.f64 2) (Rewrite=> *-commutative_binary64 (*.f64 (-.f64 (sin.f64 x) (*.f64 1/16 (sin.f64 y))) (-.f64 (sin.f64 y) (*.f64 1/16 (sin.f64 x)))))): 0 points increase in error, 0 points decrease in error
Final simplification0.4
\[\leadsto \frac{2 + \left(\mathsf{fma}\left(-0.0625, \sin y, \sin x\right) \cdot \left(\sqrt{2} \cdot \mathsf{fma}\left(-0.0625, \sin x, \sin y\right)\right)\right) \cdot \left(\cos x - \cos y\right)}{3 \cdot \left(\left(1 + \frac{\cos x}{0.5 \cdot \left(1 + \sqrt{5}\right)}\right) + \cos y \cdot \frac{\frac{4}{3 + \sqrt{5}}}{2}\right)}
\]