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Diff — Hyperbolic functions

Revision #1309 → #2032 · back to history

modifiedHyperbolic functions (geometric)f09123b427b7
FieldFrom #1309To #2032
mathlib.declReal.sinh
mathlib.match_kindinvocation
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
noteMathlib defines the hyperbolic family (`Real.sinh`/`cosh`/`tanh` and `Complex` versions) although not via the geometric framing.
statusformalized
modifiedDerivatives of sinh and coshec446089ad37
FieldFrom #1309To #2032
mathlib.declReal.deriv_sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
note`Real.deriv_sinh : deriv sinh = cosh` and `Real.deriv_cosh : deriv cosh = sinh` are both in DerivHyp.
statusformalized
modifiedHyperbolic sine5668b47e6fc3
FieldFrom #1309To #2032
mathlib.declReal.sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Real.sinh` (and `Complex.sinh`) are defined in `Mathlib.Analysis.Complex.Trigonometric`.
statusformalized
modifiedHyperbolic cosine7ee178637c3b
FieldFrom #1309To #2032
mathlib.declReal.cosh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Real.cosh` and `Complex.cosh` are defined as `(exp z + exp (-z))/2`.
statusformalized
modifiedHyperbolic tangentafc315161386
FieldFrom #1309To #2032
mathlib.declReal.tanh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Real.tanh` and `Complex.tanh` are defined as `sinh/cosh`.
statusformalized
modifiedHyperbolic cotangent930aebec22cf
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo `coth`/`Real.coth`/`Complex.coth` declaration is present in Mathlib.
statusnot_formalized
modifiedHyperbolic secant5541631431f7
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo `sech` declaration is present in Mathlib.
statusnot_formalized
modifiedHyperbolic cosecant7079baef41fa
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo `csch` declaration is present in Mathlib.
statusnot_formalized
modifiedInverse hyperbolic functions2b7f704a5be6
FieldFrom #1309To #2032
mathlib.declReal.arsinh
mathlib.match_kindspecial_case
mathlib.moduleMathlib.Analysis.SpecialFunctions.Arsinh
note`Real.arsinh`, `Real.arcosh`, `Real.artanh` are defined; the other three inverses (arcoth/arsech/arcsch) are absent.
statuspartial
modifiedHyperbolic anglee2d8138254a6
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo formalization of hyperbolic angle / hyperbolic sector area in Mathlib.
statusnot_formalized
modifiedsinh and cosh are entire4b1239d14fa9
FieldFrom #1309To #2032
mathlib.declComplex.analyticOnNhd_sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
note`Complex.analyticOnNhd_sinh`/`analyticOnNhd_cosh` (and `differentiable_sinh`/`differentiable_cosh`) state that they are entire.
statusformalized
modifiedOther hyperbolic functions meromorphic74f72019cf48
FieldFrom #1309To #2032
mathlib.declComplex.meromorphic_tanh
mathlib.match_kindspecial_case
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.Meromorphic
noteOnly `Complex.meromorphic_tanh` is formalized; coth/sech/csch are not even defined.
statuspartial
modifiedTranscendence via Lindemann–Weierstrass0b349a2e8f30
FieldFrom #1309To #2032
mathlib.declLindemannWeierstrass.exp_polynomial_approx
mathlib.match_kindinvocation
mathlib.moduleMathlib.NumberTheory.Transcendental.Lindemann.AnalyticalPart
noteOnly the analytical part of Lindemann–Weierstrass is in Mathlib; the corollary for hyperbolic values is not stated.
statuspartial
modifiedExponential definition (sinh and cosh)c88729ff97bf
FieldFrom #1309To #2032
mathlib.declReal.sinh_eq
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Real.sinh_eq`/`Real.cosh_eq` give the exponential formulas; the Complex versions are the literal definitions.
statusformalized
modifiedHyperbolic sine as odd part of exp4ccf7eaf821f
FieldFrom #1309To #2032
mathlib.declComplex.sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
noteThe Mathlib definition `Complex.sinh z = (exp z - exp (-z))/2` is literally the odd part of `exp`.
statusformalized
modifiedHyperbolic cosine as even part of expeffdad0d581d
FieldFrom #1309To #2032
mathlib.declComplex.cosh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.cosh z := (exp z + exp (-z))/2` is the even part of `exp`.
statusformalized
modifiedHyperbolic tangent (exponential)17d8ab9332c4
FieldFrom #1309To #2032
mathlib.declReal.tanh_eq
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Real.tanh_eq` gives `tanh x = (exp x - exp(-x))/(exp x + exp(-x))`.
statusformalized
modifiedHyperbolic cotangent (exponential)28833fde6f96
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo coth function or exponential identity for it is in Mathlib.
statusnot_formalized
modifiedHyperbolic secant (exponential)3896bb40d26b
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo sech function is defined in Mathlib.
statusnot_formalized
modifiedHyperbolic cosecant (exponential)9d614b243536
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo csch function is defined in Mathlib.
statusnot_formalized
modifiedSinh and cosh via ODE systeme38d5d8ae928
FieldFrom #1309To #2032
mathlib.declReal.hasDerivAt_sinh
mathlib.match_kindinvocation
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
noteMathlib has `hasDerivAt_sinh`/`hasDerivAt_cosh` (so sinh'=cosh, cosh'=sinh) but does not characterize sinh/cosh as the unique solution of this ODE system.
statuspartial
modifiedSinh and cosh as solutions of f''=fa6df5b406dfe
FieldFrom #1309To #2032
mathlib.declReal.deriv_sinh
mathlib.match_kindinvocation
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
noteThat sinh''=sinh and cosh''=cosh is derivable from `deriv_sinh = cosh`/`deriv_cosh = sinh`, but the uniqueness statement is not formalized.
statuspartial
modifiedHyperbolic functions via complex trig5b088a820c4f
FieldFrom #1309To #2032
mathlib.declComplex.sinh_mul_I
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.sinh_mul_I : sinh (x*I) = sin x * I` and `Complex.cosh_mul_I : cosh (x*I) = cos x` capture this relationship.
statusformalized
modifiedArea under cosh equals arc length79f4a8c72685
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo statement about area-under-cosh equalling arc length is in Mathlib.
statusnot_formalized
modifiedTanh as ODE solutionc635c7164dbf
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo ODE-uniqueness characterization of tanh is in Mathlib.
statusnot_formalized
modifiedOsborn's rule38d84029d5e6
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteOsborn's rule (sign convention for converting trig identities to hyperbolic) is not formalized.
statusnot_formalized
modifiedOdd and even functions8bf9e3d63d26
FieldFrom #1309To #2032
mathlib.declComplex.sinh_neg
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`sinh_neg : sinh (-x) = -sinh x` and `cosh_neg : cosh (-x) = cosh x` are in Mathlib for both `Real` and `Complex`.
statusformalized
modifiedReciprocals581e5a05df10
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteSince coth/sech/csch are not defined, their reciprocal identities are not formalized.
statusnot_formalized
modifiedAnalogue of Euler's formula98117c0ab933
FieldFrom #1309To #2032
mathlib.declComplex.cosh_add_sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.cosh_add_sinh : cosh x + sinh x = exp x` (and `Real` version) formalize the hyperbolic Euler analogue.
statusformalized
modifiedHyperbolic Pythagorean identityb6eb7993ed32
FieldFrom #1309To #2032
mathlib.declComplex.cosh_sq_sub_sinh_sq
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.cosh_sq_sub_sinh_sq : cosh x ^ 2 - sinh x ^ 2 = 1` (and Real version).
statusformalized
modifiedSums and differences of argumentsdf5b275c3ef7
FieldFrom #1309To #2032
mathlib.declComplex.sinh_add
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.sinh_add`, `cosh_add`, `sinh_sub`, `cosh_sub` are all in Mathlib for `Real` and `Complex`.
statusformalized
modifiedHalf argument formulas29201ac6b365
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteHalf-angle formulas for sinh/cosh in terms of the sign function are not formalized for arbitrary real arguments.
statusnot_formalized
modifiedHalf argument formula for nonzero x68a8cc9660e5
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteThe half-argument formula for nonzero x is not in Mathlib.
statusnot_formalized
modifiedTangent half argument formulaa3e85fbdf5c5
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo tanh half-argument formula appears in Mathlib.
statusnot_formalized
modifiedStatistical inequality for hyperbolic functionsdb97b1293a6f
FieldFrom #1309To #2032
mathlib.declReal.cosh_le_exp_half_sq
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.Series
note`Real.cosh_le_exp_half_sq : cosh x ≤ exp (x^2/2)` is the inequality used in statistics (e.g. Hoeffding).
statusformalized
modifiedSinh and cosh equal their second derivativesf9485269c656
FieldFrom #1309To #2032
mathlib.declReal.deriv_sinh
mathlib.match_kindinvocation
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
noteFollows directly from `deriv_sinh = cosh` and `deriv_cosh = sinh`, but no dedicated `sinh'' = sinh` lemma is stated.
statuspartial
modifiedFunctions equal to own second derivativee2683eeb065c
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo general classification of solutions of f''=f as span{sinh,cosh} is formalized.
statusnot_formalized
modifiedIntegrals via hyperbolic substitutiona8e0d260096c
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteIntegrals of 1/√(x²±a²), etc. via hyperbolic substitution are not in Mathlib.
statusnot_formalized
modifiedTaylor series of sinhd36f109a5b99
FieldFrom #1309To #2032
mathlib.declReal.sinh_eq_tsum
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.Series
note`Real.sinh_eq_tsum`/`Complex.sinh_eq_tsum` give `sinh x = ∑ x^(2n+1)/(2n+1)!`.
statusformalized
modifiedTaylor series of cosh4d61733380ce
FieldFrom #1309To #2032
mathlib.declReal.cosh_eq_tsum
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.Series
note`Real.cosh_eq_tsum`/`Complex.cosh_eq_tsum` give `cosh x = ∑ x^(2n)/(2n)!`.
statusformalized
modifiedSum of sinh and cosh seriesa2be5ea5045b
FieldFrom #1309To #2032
mathlib.declComplex.sinh_add_cosh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.sinh_add_cosh : sinh x + cosh x = exp x` (plus the tsum identities) gives this; combined with `cosh_eq_tsum`/`sinh_eq_tsum` the series-sum form follows.
statusformalized
modifiedInfinite product expansionsea3e907aff69
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo Weierstrass-product expansions of sinh/cosh appear in Mathlib.
statusnot_formalized
modifiedHyperbolic angle invariance under squeeze mapping509649c72f6b
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteNo formalization of squeeze mappings or hyperbolic-angle invariance.
statusnot_formalized
modifiedGudermannian function relation81e80700abd6
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteThe Gudermannian function is not defined in Mathlib.
statusnot_formalized
modifiedCatenary as graph of cosh6373f5ca475c
FieldFrom #1309To #2032
mathlib.decl
mathlib.match_kind
mathlib.module
noteThe catenary curve is not formalized in Mathlib.
statusnot_formalized
modifiedExponential decomposition into sinh and coshb7fea8e8bd4c
FieldFrom #1309To #2032
mathlib.declComplex.cosh_add_sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.cosh_add_sinh : cosh x + sinh x = exp x` and `Complex.cosh_sub_sinh : cosh x - sinh x = exp (-x)` give the decomposition.
statusformalized
modifiedHyperbolic functions for complex arguments8a4fdc94dcdd
FieldFrom #1309To #2032
mathlib.declComplex.sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.Complex.Trigonometric
note`Complex.sinh`, `Complex.cosh`, `Complex.tanh` are defined directly on `ℂ`.
statusformalized
modifiedsinh z and cosh z are holomorphic1d2c2bb13095
FieldFrom #1309To #2032
mathlib.declComplex.analyticOnNhd_sinh
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.DerivHyp
note`Complex.analyticOnNhd_sinh`/`analyticOnNhd_cosh` (and `differentiable_sinh`/`differentiable_cosh`) state holomorphicity.
statusformalized
modifiedPeriodicity in imaginary component59e0628334ed
FieldFrom #1309To #2032
mathlib.declComplex.sinh_periodic
mathlib.match_kindexact
mathlib.moduleMathlib.Analysis.SpecialFunctions.Trigonometric.Basic
note`Complex.sinh_periodic`/`cosh_periodic` give period `2π·I`, and `tanh_periodic` gives period `π·I`.
statusformalized
addedAddition and subtraction formulas123458161628
addedProduct formulas92f9ce61f1f9
addedSquare formulas2567832d168d
addedInverse hyperbolic functions as logarithms879452098363
addedDerivatives of hyperbolic functions261b94e44c2d
addedStandard integrals of hyperbolic functions239f4949e719
addedTaylor series convergence on complex plane (sinh)9a34fda8f8dd
addedTaylor series convergence on complex plane (cosh)5d9edb3a5df2
addedCircular sector area equals angle when r=√2b5c9c560da68
addedComplex exponential via sinh and cosh5d3bde79aabe