Nuprl Lemma : arctangent-reduction
∀B:{B:ℝ| r0 < B} . ∀x:{x:ℝ| (r(-1)/B) < x} .  (arctangent(x) = (arctangent(B) + arctangent((x - B/r1 + (x * B)))))
Proof
Definitions occuring in Statement : 
arctangent: arctangent(x)
, 
rdiv: (x/y)
, 
rless: x < y
, 
rsub: x - y
, 
req: x = y
, 
rmul: a * b
, 
radd: a + b
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
set: {x:A| B[x]} 
, 
minus: -n
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
sq_stable: SqStable(P)
, 
implies: P 
⇒ Q
, 
squash: ↓T
, 
prop: ℙ
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
uiff: uiff(P;Q)
, 
nat: ℕ
, 
decidable: Dec(P)
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
false: False
, 
rev_implies: P 
⇐ Q
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
true: True
, 
rdiv: (x/y)
, 
req_int_terms: t1 ≡ t2
, 
rge: x ≥ y
, 
so_lambda: λ2x.t[x]
, 
rfun: I ⟶ℝ
, 
so_apply: x[s]
, 
rfun-eq: rfun-eq(I;f;g)
, 
r-ap: f(x)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
subtype_rel: A ⊆r B
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
i-member: r ∈ I
, 
roiint: (l, ∞)
, 
concave-on: concave-on(I;x.f[x])
, 
cand: A c∧ B
, 
nat_plus: ℕ+
, 
rat_term_to_real: rat_term_to_real(f;t)
, 
rtermDivide: num "/" denom
, 
rat_term_ind: rat_term_ind, 
rtermConstant: "const"
, 
rtermVar: rtermVar(var)
, 
pi1: fst(t)
, 
rtermMultiply: left "*" right
, 
pi2: snd(t)
Lemmas referenced : 
real_wf, 
rless_wf, 
rdiv_wf, 
int-to-real_wf, 
sq_stable__rless, 
radd_wf, 
rmul_wf, 
rmul_preserves_rless, 
rnexp2-nonneg, 
derivative-arctangent, 
rinv_wf2, 
rminus_wf, 
itermSubtract_wf, 
itermMultiply_wf, 
itermConstant_wf, 
itermVar_wf, 
itermMinus_wf, 
rless-implies-rless, 
rsub_wf, 
itermAdd_wf, 
req-iff-rsub-is-0, 
rnexp_wf, 
decidable__le, 
full-omega-unsat, 
intformnot_wf, 
intformle_wf, 
istype-int, 
int_formula_prop_not_lemma, 
istype-void, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
istype-le, 
trivial-rless-radd, 
rless-int, 
rless_functionality, 
req_transitivity, 
rminus_functionality, 
rmul-rinv, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_mul_lemma, 
real_term_value_const_lemma, 
real_term_value_var_lemma, 
real_term_value_minus_lemma, 
real_term_value_add_lemma, 
rless_functionality_wrt_implies, 
rleq_weakening_equal, 
radd_functionality_wrt_rleq, 
antiderivatives-equal, 
roiint_wf, 
iproper-roiint, 
i-member_wf, 
arctangent_wf, 
member_roiint_lemma, 
riiint_wf, 
req_weakening, 
subinterval-riiint, 
derivative_functionality2, 
rnexp-positive, 
arctangent-chain-rule, 
req_functionality, 
rdiv_functionality, 
rnexp_functionality, 
radd_functionality, 
rmul_functionality, 
req_wf, 
derivative-rdiv, 
istype-top, 
subtype_rel_dep_function, 
top_wf, 
concave-positive-nonzero-on, 
rleq_weakening, 
rccint_wf, 
member_riiint_lemma, 
true_wf, 
istype-true, 
derivative-sub, 
derivative-id, 
derivative-const, 
derivative-add, 
derivative-const-mul2, 
rmul-is-positive, 
nat_plus_properties, 
sq_stable__rneq, 
rmul_comm, 
derivative_functionality, 
rnexp2, 
derivative-add-const, 
rdiv-rdiv, 
rmul-rinv3, 
squash_wf, 
subtype_rel_self, 
iff_weakening_equal, 
req_inversion, 
rless_transitivity1, 
assert-rat-term-eq2, 
rtermDivide_wf, 
rtermVar_wf, 
rtermMultiply_wf, 
rtermConstant_wf, 
square-nonneg, 
rmul_preserves_req, 
uiff_transitivity, 
arctangent_functionality, 
arctangent0
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
setIsType, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
closedConclusion, 
minusEquality, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
independent_isectElimination, 
sqequalRule, 
inrFormation_alt, 
dependent_functionElimination, 
hypothesisEquality, 
independent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
productElimination, 
inhabitedIsType, 
dependent_set_memberEquality_alt, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
int_eqEquality, 
equalityTransitivity, 
equalitySymmetry, 
applyEquality, 
setEquality, 
inlFormation_alt, 
productIsType, 
equalityIstype, 
instantiate, 
universeEquality
Latex:
\mforall{}B:\{B:\mBbbR{}|  r0  <  B\}  .  \mforall{}x:\{x:\mBbbR{}|  (r(-1)/B)  <  x\}  .
    (arctangent(x)  =  (arctangent(B)  +  arctangent((x  -  B/r1  +  (x  *  B)))))
Date html generated:
2019_10_31-AM-06_08_00
Last ObjectModification:
2019_04_03-AM-00_28_15
Theory : reals_2
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