?

\[\tan^{-1} \left(N + 1\right) - \tan^{-1} N \]

(FPCore (N) :precision binary64 (- (atan (+ N 1.0)) (atan N)))

double code(double N) {
	return atan((N + 1.0)) - atan(N);
}

real(8) function code(n)
    real(8), intent (in) :: n
    code = atan((n + 1.0d0)) - atan(n)
end function

public static double code(double N) {
	return Math.atan((N + 1.0)) - Math.atan(N);
}

def code(N):
	return math.atan((N + 1.0)) - math.atan(N)

function code(N)
	return Float64(atan(Float64(N + 1.0)) - atan(N))
end

function tmp = code(N)
	tmp = atan((N + 1.0)) - atan(N);
end

code[N_] := N[(N[ArcTan[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[ArcTan[N], $MachinePrecision]), $MachinePrecision]

\tan^{-1} \left(N + 1\right) - \tan^{-1} N

Reproduce?

Please include this information when filing a bug report:

herbie shell --seed 2023241 
(FPCore (N)
  :name "2atan (example 3.5)"
  :precision binary64

  :herbie-target
  (atan (/ 1.0 (+ 1.0 (* N (+ N 1.0)))))

  (- (atan (+ N 1.0)) (atan N)))

Backtrace

match: no matching clause for 'ival		L	C
compile-progs	/home/nightlies/herbie/arb-support/src/programs.rkt	122	0
make-search-func	/home/nightlies/herbie/arb-support/src/ground-truth.rkt	20	0
sample-points	/home/nightlies/herbie/arb-support/src/ground-truth.rkt	64	0
setup-context!	/home/nightlies/herbie/arb-support/src/mainloop.rkt	293	0
get-alternatives/report	/home/nightlies/herbie/arb-support/src/sandbox.rkt	148	0
(unnamed)	/home/nightlies/herbie/arb-support/src/sandbox.rkt	247	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24