Nuprl Lemma : rtan_wf

x:{x:ℝx ∈ (-(π/2), π/2)} (rtan(x) ∈ ℝ)


Proof




Definitions occuring in Statement :  rtan: rtan(x) halfpi: π/2 rooint: (l, u) i-member: r ∈ I rminus: -(x) real: all: x:A. B[x] member: t ∈ T set: {x:A| B[x]} 
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T rtan: rtan(x) uall: [x:A]. B[x] uimplies: supposing a rneq: x ≠ y guard: {T} or: P ∨ Q prop: so_lambda: λ2x.t[x] so_apply: x[s]
Lemmas referenced :  rcos-positive rdiv_wf rsin_wf rcos_wf rless_wf int-to-real_wf set_wf real_wf i-member_wf rooint_wf rminus_wf halfpi_wf
Rules used in proof :  cut introduction extract_by_obid sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation hypothesis sqequalHypSubstitution dependent_functionElimination thin hypothesisEquality setElimination rename sqequalRule isectElimination because_Cache independent_isectElimination inrFormation natural_numberEquality lambdaEquality

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



Date html generated: 2018_05_22-PM-02_59_16
Last ObjectModification: 2017_10_19-PM-05_19_05

Theory : reals_2


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