Question 6. In Example 2.4.3, show that f(r) converges to 0 at each r E [0, 1].

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Chapter2: Second-order Linear Odes
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Question

. In Example 2.4.3, show that fn(x) converges to 0 at each x ∈ [0, 1].

Define fn by
fn(x) = n X(0, 1
n ](x) = n if 0 < x ≤ 1
n ,
0 otherwise.
In this case limn→∞ fn(x) = 0 for all x ∈ [0, 1]. So here is an example
where the pointwise limit of a sequence of Lebesgue integrable functions is Lebesgue integrable. The odd thing is that  1
0
fn = 1 for
every n, but  1
0
0 = 0. In other words, here is an example where
limn→∞  b
a
fn =
 b
a

limn→∞ fn


Question 6. In Example 2.4.3, show that fn (2) converges to 0 at each r € [0, 1].
Transcribed Image Text:Question 6. In Example 2.4.3, show that fn (2) converges to 0 at each r € [0, 1].
Example 2.4.3. Define f. by
n if 0<r<
fa(x) = n X(@2(x) = {
%3D
(0.
otherwise.
In this case lim fn(x) 0 for all r E (0,1]. So here is an example
where the pointwise limit of a sequence of Lebesgue integrable fune-
tions is Lebesgue integrable. The odd thing is that fn = 1 for
every n, but
0 = 0. In other words, here is an example where
lim
What we are seeking are conditions that allow us to interchange
two limit-type operations, namely, integration (Lebesgue integration
in this case) and the limit of a sequence of functions. Our goal is a
theorem that addresses this issue, the Lebesgue Dominated Conver-
gence Theorem. Before the statement and proof of this theorem, we
need two lemmas.
Transcribed Image Text:Example 2.4.3. Define f. by n if 0<r< fa(x) = n X(@2(x) = { %3D (0. otherwise. In this case lim fn(x) 0 for all r E (0,1]. So here is an example where the pointwise limit of a sequence of Lebesgue integrable fune- tions is Lebesgue integrable. The odd thing is that fn = 1 for every n, but 0 = 0. In other words, here is an example where lim What we are seeking are conditions that allow us to interchange two limit-type operations, namely, integration (Lebesgue integration in this case) and the limit of a sequence of functions. Our goal is a theorem that addresses this issue, the Lebesgue Dominated Conver- gence Theorem. Before the statement and proof of this theorem, we need two lemmas.
Expert Solution
Step 1

Let us consider the function :

                                 fnx=n if 0<x1n0 otherwise

We have to prove that fn(x) converges to 0 for each x[0,1]

By the definition of fn(x) for x=0fn(x)=0 n

Therefore, fn(0)0 as n.  ----------> (1)

Here we will first fix one x0(0,1] and will show that fn(x0)0 as n. Now through the arbitraryness of the x0 in (0,1] we can conclude fn(x)0 as n  x[0,1]  [ since (1) also holds ]

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