Nuprl Lemma : rabs-cosine-rleq
∀x:ℝ. (|cosine(x)| ≤ r1)
Proof
Definitions occuring in Statement : 
cosine: cosine(x), 
rleq: x ≤ y, 
rabs: |x|, 
int-to-real: r(n), 
real: ℝ, 
all: ∀x:A. B[x], 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
le: A ≤ B, 
less_than': less_than'(a;b), 
false: False, 
not: ¬A, 
prop: ℙ, 
nat_plus: ℕ+, 
less_than: a < b, 
squash: ↓T, 
true: True, 
nat: ℕ, 
uimplies: b supposing a, 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
exp: i^n, 
primrec: primrec(n;b;c), 
subtract: n - m, 
subtype_rel: A ⊆r B, 
guard: {T}, 
sq_type: SQType(T), 
rsub: x - y
Lemmas referenced : 
sine-cosine-pythag, 
real_wf, 
rnexp-rleq-iff, 
rabs_wf, 
cosine_wf, 
int-to-real_wf, 
zero-rleq-rabs, 
rleq-int, 
false_wf, 
less_than_wf, 
rnexp_wf, 
le_wf, 
rnexp2-nonneg, 
rleq_functionality, 
req_inversion, 
rabs-rnexp, 
req_weakening, 
rabs-of-nonneg, 
exp_wf2, 
subtype_base_sq, 
nat_plus_wf, 
set_subtype_base, 
int_subtype_base, 
equal_wf, 
squash_wf, 
true_wf, 
exp-one, 
iff_weakening_equal, 
radd-preserves-req, 
radd_wf, 
sine_wf, 
rminus_wf, 
req_wf, 
rmul_wf, 
rnexp-int, 
uiff_transitivity, 
req_functionality, 
req_transitivity, 
radd_functionality, 
rminus-as-rmul, 
radd-assoc, 
rmul-identity1, 
rmul-distrib2, 
rmul_functionality, 
radd-int, 
rmul-zero-both, 
radd_comm, 
radd-zero-both, 
radd-preserves-rleq, 
rsub_wf, 
rleq_wf, 
radd-ac, 
radd-rminus-both, 
radd-rminus-assoc
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isectElimination, 
natural_numberEquality, 
independent_functionElimination, 
productElimination, 
sqequalRule, 
independent_pairFormation, 
dependent_set_memberEquality, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
independent_isectElimination, 
instantiate, 
cumulativity, 
intEquality, 
lambdaEquality, 
applyEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
minusEquality, 
addEquality
Latex:
\mforall{}x:\mBbbR{}.  (|cosine(x)|  \mleq{}  r1)
 Date html generated: 
2017_10_04-PM-10_20_53
 Last ObjectModification: 
2017_07_28-AM-08_48_11
Theory : reals_2
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