Nuprl Lemma : derivative-mul-x
∀I:Interval. ∀f:I ⟶ℝ. ∀g:{h:I ⟶ℝ| ∀x,y:{t:ℝ| t ∈ I} .  ((x = y) ⇒ ((h x) = (h y)))} .
  (d(f[x])/dx = λx.g[x] on I ⇒ d(x * f[x])/dx = λx.(x * g[x]) + f[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, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x.t[x], 
label: ...$L... t, 
rfun: I ⟶ℝ, 
so_apply: x[s], 
prop: ℙ, 
uimplies: b supposing a, 
sq_stable: SqStable(P), 
squash: ↓T, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
rfun-eq: rfun-eq(I;f;g), 
r-ap: f(x), 
req_int_terms: t1 ≡ t2, 
false: False, 
not: ¬A, 
top: Top
Lemmas referenced : 
derivative_wf, 
real_wf, 
i-member_wf, 
req_wf, 
rfun_wf, 
interval_wf, 
int-to-real_wf, 
req_weakening, 
sq_stable__req, 
derivative-mul, 
derivative-id, 
rmul_wf, 
radd_wf, 
itermSubtract_wf, 
itermAdd_wf, 
itermMultiply_wf, 
itermVar_wf, 
itermConstant_wf, 
req-iff-rsub-is-0, 
derivative_functionality, 
real_polynomial_null, 
istype-int, 
real_term_value_sub_lemma, 
istype-void, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality_alt, 
applyEquality, 
setIsType, 
hypothesis, 
setElimination, 
rename, 
because_Cache, 
inhabitedIsType, 
functionIsType, 
natural_numberEquality, 
independent_isectElimination, 
independent_functionElimination, 
dependent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_set_memberEquality_alt, 
productElimination, 
approximateComputation, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination
Latex:
\mforall{}I:Interval.  \mforall{}f:I  {}\mrightarrow{}\mBbbR{}.  \mforall{}g:\{h:I  {}\mrightarrow{}\mBbbR{}|  \mforall{}x,y:\{t:\mBbbR{}|  t  \mmember{}  I\}  .    ((x  =  y)  {}\mRightarrow{}  ((h  x)  =  (h  y)))\}  .
    (d(f[x])/dx  =  \mlambda{}x.g[x]  on  I  {}\mRightarrow{}  d(x  *  f[x])/dx  =  \mlambda{}x.(x  *  g[x])  +  f[x]  on  I)
Date html generated:
2019_10_30-AM-09_01_42
Last ObjectModification:
2019_01_03-PM-00_06_08
Theory : reals
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