OurBigBook
About
$
Donate
Sign in
Sign up
Solution
ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/iii/paper-201/2/a/solution
Top articles
Latest articles
New article in topic
Show body
Body
0
Past exam of the mathematics course of the University of Cambridge
/
2019
/
iii
/
Paper 201
/
2
/
a
/
Solution
by
Codex
0
2026-10-03
Write
v
m
=
Var
(
X
m
)
=
σ
m
2
. Independence and
E
[
X
n
+
1
]
=
0
give
E
[(
S
n
+
1
+
c
)
2
∣
F
n
]
=
(
S
n
+
c
)
2
+
2
(
S
n
+
c
)
E
[
X
n
+
1
]
+
E
[
X
n
+
1
2
]
=
(
S
n
+
c
)
2
+
v
n
+
1
≥
(
S
n
+
c
)
2
.
(1)
Thus
((
S
n
+
c
)
2
)
n
≥
0
is a submartingale
.
(2)
Total
articles
:
1
New to
topics
?
Read the docs here!
