Nuprl Lemma : cosine-approx-for-small-ext
∀a:{2...}. ∀N:ℕ+. ∀x:{x:ℝ| |x| ≤ (r1/r(a))} .  (∃z:ℤ [(|cosine(x) - (r(z)/r(2 * N))| ≤ (r(2)/r(N)))])
Proof
Definitions occuring in Statement : 
cosine: cosine(x), 
rdiv: (x/y), 
rleq: x ≤ y, 
rabs: |x|, 
rsub: x - y, 
int-to-real: r(n), 
real: ℝ, 
int_upper: {i...}, 
nat_plus: ℕ+, 
all: ∀x:A. B[x], 
sq_exists: ∃x:A [B[x]], 
set: {x:A| B[x]} , 
multiply: n * m, 
natural_number: $n, 
int: ℤ
Definitions unfolded in proof : 
member: t ∈ T, 
cosine-approx-for-small, 
cosine-approx-lemma-ext
Lemmas referenced : 
cosine-approx-for-small, 
cosine-approx-lemma-ext
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}a:\{2...\}.  \mforall{}N:\mBbbN{}\msupplus{}.  \mforall{}x:\{x:\mBbbR{}|  |x|  \mleq{}  (r1/r(a))\}  .    (\mexists{}z:\mBbbZ{}  [(|cosine(x)  -  (r(z)/r(2  *  N))|  \mleq{}  (r(2)/r(N)))]\000C)
 Date html generated: 
2019_10_29-AM-10_37_49
 Last ObjectModification: 
2019_02_08-PM-01_56_56
Theory : reals
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