Nuprl Lemma : arctangent-reduction-1
∀x:{x:ℝ| r(-1) < x} . (arctangent(x) = (MachinPi4() + arctangent((x - r1/r1 + x))))
Proof
Definitions occuring in Statement : 
MachinPi4: MachinPi4()
, 
arctangent: arctangent(x)
, 
rdiv: (x/y)
, 
rless: x < y
, 
rsub: x - y
, 
req: x = y
, 
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
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
uiff: uiff(P;Q)
, 
rdiv: (x/y)
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
not: ¬A
, 
top: Top
, 
subtype_rel: A ⊆r B
, 
sq_stable: SqStable(P)
, 
rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced : 
arctangent-reduction, 
rless-int, 
int-to-real_wf, 
rless_wf, 
set_wf, 
real_wf, 
rdiv_wf, 
rmul_wf, 
rinv_wf2, 
rminus_wf, 
itermSubtract_wf, 
itermMultiply_wf, 
itermConstant_wf, 
itermVar_wf, 
itermMinus_wf, 
req-iff-rsub-is-0, 
rless_functionality, 
req_transitivity, 
rminus_functionality, 
rinv1, 
req_weakening, 
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, 
sq_stable__req, 
arctangent_wf, 
radd_wf, 
MachinPi4_wf, 
rsub_wf, 
rless-implies-rless, 
itermAdd_wf, 
real_term_value_add_lemma, 
radd_functionality, 
req_functionality, 
arctangent_functionality, 
rmul_functionality, 
rinv_functionality2, 
rinv-mul-as-rdiv, 
rinv-as-rdiv, 
pi_wf, 
req_wf, 
arctangent1, 
equal_wf, 
req_inversion
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
natural_numberEquality, 
productElimination, 
independent_functionElimination, 
sqequalRule, 
independent_pairFormation, 
imageMemberEquality, 
hypothesisEquality, 
baseClosed, 
hypothesis, 
dependent_set_memberEquality, 
isectElimination, 
lambdaEquality, 
minusEquality, 
setElimination, 
rename, 
because_Cache, 
independent_isectElimination, 
inrFormation, 
approximateComputation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
applyEquality, 
imageElimination, 
setEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}x:\{x:\mBbbR{}|  r(-1)  <  x\}  .  (arctangent(x)  =  (MachinPi4()  +  arctangent((x  -  r1/r1  +  x))))
Date html generated:
2018_05_22-PM-03_06_28
Last ObjectModification:
2017_10_26-PM-07_48_23
Theory : reals_2
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