Nuprl Lemma : cosine-exists-ext
∀x:ℝ. ∃a:ℝ. Σi.-1^i * (x^2 * i)/(2 * i)! = a
Proof
Definitions occuring in Statement : 
series-sum: Σn.x[n] = a
, 
rnexp: x^k1
, 
int-rdiv: (a)/k1
, 
int-rmul: k1 * a
, 
real: ℝ
, 
fastexp: i^n
, 
fact: (n)!
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
multiply: n * m
, 
minus: -n
, 
natural_number: $n
Definitions unfolded in proof : 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
exp: i^n
, 
primrec: primrec(n;b;c)
, 
primtailrec: primtailrec(n;i;b;f)
, 
subtract: n - m
, 
accelerate: accelerate(k;f)
, 
cosine-exists, 
iff_weakening_equal, 
r-archimedean-rabs, 
alternating-series-converges, 
rleq_functionality, 
subsequence-converges, 
decidable__le, 
any: any x
, 
req_functionality, 
rdiv-factorial-limit-zero-from-bound, 
r-archimedean, 
rmax_lb, 
converges-iff-cauchy-ext, 
expfact-property, 
canonical-bound-property, 
fact-greater-exp, 
decidable__equal_int, 
decidable__and, 
decidable__not, 
decidable__less_than', 
decidable__int_equal, 
decidable__implies, 
decidable__false, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x y.t[x; y]
, 
top: Top
, 
so_apply: x[s1;s2]
, 
uimplies: b supposing a
Lemmas referenced : 
cosine-exists, 
lifting-strict-spread, 
istype-void, 
strict4-spread, 
lifting-strict-decide, 
lifting-strict-int_eq, 
strict4-decide, 
iff_weakening_equal, 
r-archimedean-rabs, 
alternating-series-converges, 
rleq_functionality, 
subsequence-converges, 
decidable__le, 
req_functionality, 
rdiv-factorial-limit-zero-from-bound, 
r-archimedean, 
rmax_lb, 
converges-iff-cauchy-ext, 
expfact-property, 
canonical-bound-property, 
fact-greater-exp, 
decidable__equal_int, 
decidable__and, 
decidable__not, 
decidable__less_than', 
decidable__int_equal, 
decidable__implies, 
decidable__false
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination
Latex:
\mforall{}x:\mBbbR{}.  \mexists{}a:\mBbbR{}.  \mSigma{}i.-1\^{}i  *  (x\^{}2  *  i)/(2  *  i)!  =  a
Date html generated:
2019_10_29-AM-10_35_27
Last ObjectModification:
2019_04_02-AM-10_10_15
Theory : reals
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