Nuprl Lemma : converges-to-cosine
∀x:ℝ. lim n→∞.if n=0  then r0  else (cosine((x within 1/n)) within 1/n) = cosine(x)
Proof
Definitions occuring in Statement : 
cosine: cosine(x)
, 
converges-to: lim n→∞.x[n] = y
, 
rational-approx: (x within 1/n)
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
int_eq: if a=b  then c  else d
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
converges-to: lim n→∞.x[n] = y
, 
sq_exists: ∃x:{A| B[x]}
, 
member: t ∈ T
, 
nat: ℕ
, 
nat_plus: ℕ+
, 
uall: ∀[x:A]. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
real: ℝ
, 
le: A ≤ B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
subtype_rel: A ⊆r B
, 
less_than': less_than'(a;b)
, 
true: True
, 
subtract: n - m
, 
rneq: x ≠ y
, 
guard: {T}
, 
ge: i ≥ j 
, 
so_apply: x[s]
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rge: x ≥ y
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
nequal: a ≠ b ∈ T 
, 
int_upper: {i...}
Lemmas referenced : 
nat_plus_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermMultiply_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_wf, 
nat_wf, 
all_wf, 
rleq_wf, 
rabs_wf, 
rsub_wf, 
int-to-real_wf, 
rational-approx_wf, 
cosine_wf, 
decidable__lt, 
false_wf, 
not-lt-2, 
not-equal-2, 
add_functionality_wrt_le, 
add-associates, 
add-zero, 
add-commutes, 
zero-add, 
le-add-cancel, 
condition-implies-le, 
minus-add, 
minus-zero, 
less_than_wf, 
rdiv_wf, 
rless-int, 
nat_properties, 
rless_wf, 
nat_plus_wf, 
real_wf, 
rational-approx-property, 
equal_wf, 
rleq_functionality, 
rabs-difference-symmetry, 
req_weakening, 
rabs-difference-cosine-rleq, 
rleq_functionality_wrt_implies, 
rleq_weakening_equal, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
int_upper_subtype_nat, 
nequal-le-implies, 
radd_wf, 
r-triangle-inequality2, 
int_upper_properties, 
radd_functionality_wrt_rleq, 
rmul_wf, 
rleq-int-fractions, 
uiff_transitivity, 
req_transitivity, 
radd_functionality, 
req_inversion, 
rmul-identity1, 
rmul-distrib2, 
rmul_functionality, 
radd-int, 
rmul-int-rdiv
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
dependent_set_memberFormation, 
dependent_set_memberEquality, 
multiplyEquality, 
natural_numberEquality, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
cut, 
hypothesisEquality, 
hypothesis, 
introduction, 
extract_by_obid, 
isectElimination, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
because_Cache, 
functionEquality, 
productElimination, 
independent_functionElimination, 
addEquality, 
applyEquality, 
minusEquality, 
inrFormation, 
equalityTransitivity, 
equalitySymmetry, 
equalityElimination, 
int_eqReduceTrueSq, 
promote_hyp, 
instantiate, 
cumulativity, 
int_eqReduceFalseSq, 
hypothesis_subsumption
Latex:
\mforall{}x:\mBbbR{}.  lim  n\mrightarrow{}\minfty{}.if  n=0    then  r0    else  (cosine((x  within  1/n))  within  1/n)  =  cosine(x)
Date html generated:
2017_10_04-PM-10_21_01
Last ObjectModification:
2017_07_28-AM-08_48_15
Theory : reals_2
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