Nuprl Lemma : derivative-mul
∀I:Interval. ∀f1,f2:I ⟶ℝ. ∀g1,g2:{h:I ⟶ℝ| ∀x,y:{t:ℝ| t ∈ I} .  ((x = y) 
⇒ ((h x) = (h y)))} .
  (d(f1[x])/dx = λx.g1[x] on I
  
⇒ d(f2[x])/dx = λx.g2[x] on I
  
⇒ d(f1[x] * f2[x])/dx = λx.(f1[x] * g2[x]) + (f2[x] * g1[x]) on I)
Proof
Definitions occuring in Statement : 
derivative: d(f[x])/dx = λz.g[z] on I
, 
rfun: I ⟶ℝ
, 
i-member: r ∈ I
, 
interval: Interval
, 
req: x = y
, 
rmul: a * b
, 
radd: a + b
, 
real: ℝ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
so_apply: x[s]
, 
member: t ∈ T
, 
true: True
, 
so_lambda: λ2x.t[x]
, 
rfun: I ⟶ℝ
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
label: ...$L... t
, 
sq_stable: SqStable(P)
, 
squash: ↓T
, 
r-ap: f(x)
, 
guard: {T}
Lemmas referenced : 
derivative-mul-part1, 
i-member_wf, 
real_wf, 
derivative_wf, 
set_wf, 
rfun_wf, 
all_wf, 
req_wf, 
interval_wf, 
differentiable-continuous, 
sq_stable__req, 
function-proper-continuous, 
sq_stable__all, 
req_witness, 
squash_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
sqequalHypSubstitution, 
sqequalRule, 
cut, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
natural_numberEquality, 
hypothesis, 
lambdaEquality, 
applyEquality, 
setElimination, 
rename, 
dependent_set_memberEquality, 
isectElimination, 
setEquality, 
functionEquality, 
because_Cache, 
imageMemberEquality, 
baseClosed, 
imageElimination
Latex:
\mforall{}I:Interval.  \mforall{}f1,f2:I  {}\mrightarrow{}\mBbbR{}.  \mforall{}g1,g2:\{h:I  {}\mrightarrow{}\mBbbR{}|  \mforall{}x,y:\{t:\mBbbR{}|  t  \mmember{}  I\}  .    ((x  =  y)  {}\mRightarrow{}  ((h  x)  =  (h  y)))\}  .
    (d(f1[x])/dx  =  \mlambda{}x.g1[x]  on  I
    {}\mRightarrow{}  d(f2[x])/dx  =  \mlambda{}x.g2[x]  on  I
    {}\mRightarrow{}  d(f1[x]  *  f2[x])/dx  =  \mlambda{}x.(f1[x]  *  g2[x])  +  (f2[x]  *  g1[x])  on  I)
Date html generated:
2016_10_26-AM-11_22_17
Last ObjectModification:
2016_08_28-PM-10_42_53
Theory : reals
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