Nuprl Lemma : rabs-difference-cosine-rleq

x,y:ℝ.  (|cosine(x) cosine(y)| ≤ |x y|)


Proof




Definitions occuring in Statement :  cosine: cosine(x) rleq: x ≤ y rabs: |x| rsub: y real: all: x:A. B[x]
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T implies:  Q so_lambda: λ2x.t[x] rfun: I ⟶ℝ uall: [x:A]. B[x] prop: so_apply: x[s] uimplies: supposing a top: Top true: True uiff: uiff(P;Q) and: P ∧ Q rev_uimplies: rev_uimplies(P;Q) guard: {T} rge: x ≥ y rsub: y squash: T subtype_rel: A ⊆B iff: ⇐⇒ Q rev_implies:  Q
Lemmas referenced :  mean-value-for-bounded-derivative riiint_wf iproper-riiint cosine_wf real_wf i-member_wf rminus_wf sine_wf req_wf set_wf derivative-cosine int-to-real_wf req_weakening all_wf rleq_wf rmul_wf rabs_wf rsub_wf member_riiint_lemma true_wf radd_wf rleq_weakening_equal req_functionality rminus_functionality sine_functionality all_functionality_wrt_uimplies rleq_functionality_wrt_implies rleq_functionality rmul-one-both squash_wf rabs-rminus iff_weakening_equal rabs-sine-rleq
Rules used in proof :  cut introduction extract_by_obid sqequalHypSubstitution sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity dependent_functionElimination thin hypothesis independent_functionElimination sqequalRule lambdaEquality isectElimination setElimination rename hypothesisEquality setEquality because_Cache lambdaFormation natural_numberEquality independent_isectElimination isect_memberEquality voidElimination voidEquality dependent_set_memberEquality productElimination equalityTransitivity equalitySymmetry applyEquality imageElimination imageMemberEquality baseClosed universeEquality

Latex:
\mforall{}x,y:\mBbbR{}.    (|cosine(x)  -  cosine(y)|  \mleq{}  |x  -  y|)



Date html generated: 2016_10_26-PM-00_13_35
Last ObjectModification: 2016_09_12-PM-05_39_47

Theory : reals_2


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