\[\cos \left(x + \varepsilon\right) - \cos x\]

\cos \left(x + \varepsilon\right) - \cos x

double f(double x, double eps) {
        double r7647 = x;
        double r7648 = eps;
        double r7649 = r7647 + r7648;
        double r7650 = cos(r7649);
        double r7651 = cos(r7647);
        double r7652 = r7650 - r7651;
        return r7652;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020045 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))

Backtrace

hash-ref: no value found for key key: '(* #<enode 0(117)> #<enode 192(192)>)		L	C
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/egraph.rkt	270	6
update-leader!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/egraph.rkt	265	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/main.rkt	77	2
prune-phase	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding/regraph/main.rkt	74	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	80	4
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	76	2
(unnamed)	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	56	0
(unnamed)	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/core/simplify.rkt	38	0
simplify!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	224	0
run-iter!	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	327	0
for-loop	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	365	4
run-improve47	/data/pavpan/nightlies/herbie/simplify-regraph-rebuilding-2/src/mainloop.rkt	346	0
.../more-scheme.rkt:261:28	unknown
run	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.5/collects/racket/private/more-scheme.rkt	261	28

Falling back on racket egraph because egg-herbie package not installed (more)

Reproduce

Backtrace