Nuprl Lemma : arctangent-rtan

∀[x:{x:ℝ| x ∈ (-(π/2), π/2)} ]. (arctangent(rtan(x)) = x)


Proof




Definitions occuring in Statement :  arctangent: arctangent(x),  rtan: rtan(x),  halfpi: π/2,  rooint: (l, u),  i-member: r ∈ I,  req: x = y,  rminus: -(x),  real: ℝ,  uall: ∀[x:A]. B[x],  set: {x:A| B[x]} 
Definitions unfolded in proof :  cand: A c∧ B,  exists: ∃x:A. B[x],  rtan: rtan(x),  rdiv: (x/y),  r-ap: f(x),  rfun-eq: rfun-eq(I;f;g),  req_int_terms: t1 ≡ t2,  top: Top,  rev_uimplies: rev_uimplies(P;Q),  or: P ∨ Q,  rneq: x ≠ y,  rge: x ≥ y,  true: True,  squash: ↓T,  less_than: a < b,  rev_implies: P ⇐ Q,  iff: P ⇐⇒ Q,  uimplies: b supposing a,  uiff: uiff(P;Q),  not: ¬A,  false: False,  less_than': less_than'(a;b),  and: P ∧ Q,  le: A ≤ B,  nat: ℕ,  guard: {T},  so_apply: x[s],  prop: ℙ,  rfun: I ⟶ℝ,  so_lambda: λ2x.t[x],  implies: P ⇒ Q,  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x]
Lemmas referenced :  rtan0,  arctangent_functionality,  arctangent0,  real_term_value_minus_lemma,  itermMinus_wf,  halfpi-positive,  rmul-zero-both,  rless_functionality,  rmul_reverses_rless_iff,  member_rooint_lemma,  rsin-rcos-pythag,  radd_comm,  rmul-rinv,  rnexp-rdiv,  req_inversion,  rsin_wf,  real_term_value_add_lemma,  real_term_value_mul_lemma,  rinv-as-rdiv,  rmul-rinv3,  req_transitivity,  rmul-identity1,  itermAdd_wf,  itermConstant_wf,  itermMultiply_wf,  rinv_wf2,  rmul_preserves_req,  derivative_functionality,  rmul_wf,  real_term_value_const_lemma,  real_term_value_var_lemma,  real_term_value_sub_lemma,  real_polynomial_null,  req-iff-rsub-is-0,  itermVar_wf,  itermSubtract_wf,  member_riiint_lemma,  all_wf,  rleq_wf,  rleq_weakening,  rtan_functionality_wrt_rleq,  rleq_functionality_wrt_implies,  monotone-maps-compact,  rdiv_functionality,  radd_functionality,  rcos_functionality,  rnexp_functionality,  req_functionality,  req_weakening,  derivative-arctangent,  derivative-rtan,  req_wf,  iproper-riiint,  rless_wf,  rdiv_wf,  riiint_wf,  chain-rule,  radd_functionality_wrt_rleq,  rleq_weakening_equal,  rless_functionality_wrt_implies,  rless-int,  trivial-rless-radd,  rnexp_wf,  radd_wf,  le_wf,  false_wf,  rcos_wf,  rnexp-positive,  rcos-positive,  rnexp2-nonneg,  set_wf,  req_witness,  derivative-id,  rtan_wf,  arctangent_wf,  i-member_wf,  real_wf,  int-to-real_wf,  halfpi-interval-proper,  halfpi_wf,  rminus_wf,  rooint_wf,  antiderivatives-equal
Rules used in proof :  productEquality,  minusEquality,  dependent_pairFormation,  intEquality,  int_eqEquality,  approximateComputation,  voidEquality,  voidElimination,  isect_memberEquality,  functionEquality,  inlFormation,  inrFormation,  equalitySymmetry,  equalityTransitivity,  baseClosed,  imageMemberEquality,  independent_isectElimination,  productElimination,  independent_pairFormation,  dependent_set_memberEquality,  lambdaFormation,  isect_memberFormation,  rename,  setElimination,  because_Cache,  hypothesisEquality,  setEquality,  natural_numberEquality,  lambdaEquality,  sqequalRule,  independent_functionElimination,  hypothesis,  isectElimination,  thin,  dependent_functionElimination,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution,  sqequalHypSubstitution,  extract_by_obid,  introduction,  cut

Latex:
\mforall{}[x:\{x:\mBbbR{}|  x  \mmember{}  (-(\mpi{}/2),  \mpi{}/2)\}  ].  (arctangent(rtan(x))  =  x)



Date html generated: 2018_05_22-PM-03_02_23
Last ObjectModification: 2018_05_20-PM-11_09_57

Theory : reals_2


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