image PNG : /home/_math/_exercice/d6/6722/metapost/bouton.png
E.5042
Justify
that,
in
each
question,
the
infor-mation
below
does
not
define
sequences
:
a
u
0
=
5
;
u
n
+1
=
2
·
u
n
−
3
for
all
n
∈
N
∗
b
u
0
=
1
;
u
1
=
4
;
u
n
+1
=
u
n
−
3
for
all
n
∈
N
c
u
0
=
3
;
u
n
=
2
·
u
n
−
1
−
2
for
all
n
∈
N
d
u
0
=
−
1
;
u
n
=
u
n
−
1
−
2
u
n
−
1
+
1
for
all
n
∈
N
∗
3.
Limits
of
arithmetic
and
geometric
sequences
E.6726
1
Consider
the
sequence
u
n
arithmetic
with
first
term
−
4
and
reason
5
:
a
Complete
the
table
below
:
n
0
1
2
3
4
5
6
7
u
n
−
4
1
6
11
16
21
b
What
conjecture
can
be
made
about
the
value
of
the
term
u
n
as
the
rank
n
becomes
larger
and
larger?
Note:
lim
n
↦→
+
∞
u
n
=
:
:
:
:
:
:
2
Consider
the
sequence
v
n
arithmetic
of
first
term
3
and
reason
−
1.2
:
a
Complete
the
table
below
:
n
0
1
2
3
4
5
6
7
v
n
3
1.8
0.6
−
0.6
−
1.8
−
3
b
What
conjecture
can
be
made
about
the
value
of
the
term
v
n
as
the
rank
n
becomes
larger
and
larger?
Note:
lim
n
↦→
+
∞
v
n
=
:
:
:
:
:
:
E.6727
1
Consider
the
sequence
u
n
geometric
with
first
term
4
and
reason
2
:
a
Complete
the
table
below
:
n
0
1
2
3
4
5
6
7
u
n
4
8
16
32
64
128
b
What
conjecture
can
be
made
about
the
value
of
the
term
u
n
as
the
rank
n
becomes
larger
and
larger?
Note:
lim
n
↦→
+
∞
u
n
=
:
:
:
:
:
:
2
Consider
the
sequence
v
n
geometric
with
first
term
81
and
reason
1
3
:
a
Complete
the
table
below
:
n
0
1
2
3
4
5
6
7
v
n
81
27
9
3
1
1
3
b
What
conjecture
can
be
made
about
the
value
of
the
term
v
n
as
the
rank
n
becomes
larger
and
larger?
Note:
lim
n
↦→
+
∞
v
n
=
:
:
:
:
:
:
E.6728
Consider
the
sequence
u
n
geometric
with
first
term
2.8
and
reason
0.9
.
1
Using
the
calculator,
complete
the
table
below
using
val-ues
approximated
to
the
hundredth
:
n
0
1
2
3
4
5
6
7
u
n
2.8
2.52
2.268
2.041
2
Using
the
calculator,
what
conjecture
can
be
made
for
the
limit
of
the
terms
in
the
sequence
u
n
?
We
note
:
lim
n
↦→
+
∞
u
n
=
:
:
:
E.2557
1
Consider
the
sequence
u
n
n
∈
N
defined
explicitly
by:
u
n
=
9
n
−
5
a
Determine
the
nature
of
the
sequence
u
n
,
specifying
its
characteristics.
b
Determine
the
limit
of
the
sequence
u
n
.
2
Consider
the
sequence
v
n
n
∈
N
defined
explicitly
by:
v
n
=
2
·
1
3
n
a
Determine
the
nature
of
the
sequence
v
n
,
specifying
its
characteristics.
b
Determine
the
limit
of
the
sequence
v
n
.
E.6729
Give,
if
possible,
the
limits
of
the
follow-ing
sequences
:
1
The
sequence
u
n
is
geometric
with
strictly
negative
first
term
and
reason
2
.
2
The
sequence
v
n
is
geometric
with
strictly
positive
first
term
and
reason
−
3
.
3
The
suite
w
n
is
geometric
with
strictly
negative
first
term
and
reason
−
0.2
.
4.
Sum
limits
of
terms
of
sequences
E.2559
1
Let
u
n
n
∈
N
be
the
arithmetic
sequence
of
first
term
2
and
reason
−
1
.
a
Determine
the
explicit
expression
of
the
terms
of
the
sequence
as
a
function
of
rank
n
.
b
Note
S
n
=
u
0
+
u
1
+
···
+
u
n
the
sum
of
the
first
(
n
+1)
terms
of
the
sequence.
Give
the
expression
of
S
n
as
a
https://chingmath.fr
chapExoCorrec/5042
sacados/5042
chapExoCorrec/6726
sacados/6726
chapExoCorrec/6727
sacados/6727
chapExoCorrec/6728
sacados/6728
chapExoCorrec/2557
sacados/2557
chapExoCorrec/6729
sacados/6729
chapExoCorrec/2559
sacados/2559
function
of
n
.
c
Deduce
the
limit:
lim
n
↦→
+
∞
S
n
.
2
Let
v
n
n
∈
N
be
the
geometric
sequence
of
first
term
5
and
reason
1
2
.
a
Determine
the
explicit
expression
of
the
terms
of
the
sequence
as
a
function
of
rank
n
.
b
Note
S
n
=
v
0
+
v
1
+
···
+
v
n
the
sum
of
the
first
(
n
+1)
terms
of
the
sequence.
Give
the
expression
of
S
n
as
a
function
of
n
.
c
Deduce
the
limit:
lim
n
↦→
+
∞
S
n
.
E.2588
Let
u
n
n
∈
N
be
a
geometric
sequence
of
first
term
2
and
reason
2
5
:
1
Determine
the
first
three
terms
of
this
sequence.
2
a
Determine
the
expression
of
the
sum
of
the
first
n
+1
terms
of
this
sequence
as
a
function
of
n
.
b
Deduce
the
value
of
the
following
limit:
lim
n
↦→
+
∞
u
0
+
u
1
+
·
·
·
+
u
n
E.2622
Consider
the
sequence
u
n
n
∈
N
geomet-ric
with
first
term
4
×
5
2
and
reason
1
5
and
sum
S
n
defined
by:
S
n
=
u
3
+
u
4
+
·
·
·
+
u
n
for
any
n
5
1
Determine
the
expression
of
S
n
as
a
function
of
n
.
2
Justify
that
the
sequence
S
n
converges
to
1.
E.2621
Consider
the
sequence
u
n
n
∈
N
geomet-ric
of
first
term
1
and
reason
1
2
and
the
sequence
(
R
n
)
defined,
for
n
2
,
by
the
sum
:
R
n
=
u
n
+
u
n
+1
+
·
·
·
+
u
2
n
Determine
the
limit
of
the
sequence
(
R
n
)
.
E.3105
Determine
and
justify
the
limits
of
the
following
amounts
:
a
S
=
1
2
+
1
2
2
+
1
2
3
+
·
·
·
+
1
2
n
b
S
=
−
15
4
+5
×
3
4
2
−
5
×
3
4
3
+5
×
3
4
4
+
···
+5
×
−
3
4
n
E.6174
A
runner
sets
himself
a
challenge
:
he
wants
to
circumnavigate
Europe.
On
the
first
day,
he
covers
50
km
.
Through
fatigue,
from
day
to
day,
his
daily
distance
travelled
is
reduced
by
1
%
.
We
note
u
n
the
length
covered
by
the
runner
on
the
n
-th
day.
Assuming
that
the
runner
continues
his
run
indefinitely,
we
obtain
a
sequence
u
n
defined
for
any
non-zero
natural
number.
1
Determine
the
value
of
the
first
four
terms
of
the
se-quence
u
n
.
2
a
What
is
the
nature
of
the
sequence
u
n
?
Give
the
characteristic
elements
of
the
sequence
u
n
.
b
Express
the
term
u
n
as
a
function
of
rank
n
.
c
What
distance
will
the
runner
cover
on
100
e
day?
We’ll
round
the
value
to
the
tenth
of
a
kilometer.
3
Note
S
the
sum
of
the
first
n
terms
of
the
sequence
u
n
:
S
n
=
u
1
+
u
2
+
·
·
·
+
u
n
a
Express
the
sum
S
n
as
a
function
of
rank
n
.
b
Complete
the
following
table,
rounding
values
to
the
nearest
tenth
of
a
kilometer:
n
10
100
500
750
1000
S
n
c
What
conjecture
can
be
made
about
the
limit
of
the
sum
S
n
when
the
value
of
n
becomes
larger
and
larger?
E.2560
A
globetrotter
has
bet
to
cover
5
000
km
on
foot.
He
can,
fresh
and
ready,
cover
50
km
in
a
day,
but
every
day
fatigue
builds
up
and
so
his
performance
decreases
by
1
%
every
day.
We’ll
note
d
n
the
distance
covered
during
the
n
-th
day.
1
Calculate
the
distances
d
1
,
d
2
,
d
3
covered
during
the
first
three
days.
2
What
precisely
is
the
nature
of
the
sequence?
Determine
the
value
of
d
n
as
a
function
of
n
.
3
Note
L
n
the
distance
in
kilometers
traveled
after
n
days.
L
n
=
d
1
+
d
2
+
·
·
·
+
d
n
a
Determine
the
expression
of
L
n
as
a
function
of
n
.
b
Deduce
the
limit
of
L
n
when
n
tends
towards
+
∞
.
Can
the
globetrotter
win?
c
Using
the
calculator,
determine
the
minimum
number
of
days
N
it
would
take
him
to
travel
4
999
km
E.5738
Consider
the
sequence
u
n
de-fined
on
N
by:
u
0
=
2
;
u
n
=
2
×
2
3
n
+
n
For
any
non-zero
natural
number
n
,
we
pose
:
S
n
=
n
k
=0
u
k
=
u
0
+
·
·
·
+
u
n
;
T
n
=
S
n
n
2
1
Express
the
term
S
n
in
terms
of
n
.
2
Determine
the
limit
of
the
sequence
T
n
.
5.
Other
limits
E.3397
Consider
the
function
f
defined
on
[
−
4
;
4]
whose
representative
curve
C
f
is
given
below
:
https://chingmath.fr
chapExoCorrec/2588
sacados/2588
chapExoCorrec/2622
sacados/2622
chapExoCorrec/2621
sacados/2621
chapExoCorrec/3105
sacados/3105
chapExoCorrec/6174
sacados/6174
chapExoCorrec/2560
sacados/2560
extrait de Polynesie - 2006 - Obligatoire - 4 points
chapExoCorrec/5738
sacados/5738
chapExoCorrec/3397
sacados/3397
-4-3-2-1234I-4-3-2-123JOCf
23I2JO(d
-3-2-123456I23456JOCf
Consider
the
sequence
u
n
n
∈
N
defined
by
the
relation:
u
0
=
2
;
u
n
+1
=
f
u
n
1
Show
that
the
term
u
1
is
equal
to
−
3
.
2
Justify
the
following
equalities:
a
u
2
=
−
0.5
b
u
3
=
2.5
3
Complete
the
following
table
:
n
0
1
2
3
4
5
6
7
8
9
u
n
4
What
can
be
said
about
the
limit
of
the
terms
of
the
sequence
u
n
?
E.3411
Consider
the
sequence
u
n
n
∈
N
defined
by
the
recurrence
relation:
u
0
=
5
2
;
u
n
+1
=
−
1
2
·
u
n
+
3
2
for
any
n
∈
N
The
graph
below
represents,
in
a
reference
frame
O
;
I
;
J
orthonormal,
the
straight
line
(
d
)
having
equation
:
y
=
−
1
2
·
x
+
3
2
1
Graphically,
on
the
x-axis
represented
the
first
five
terms
of
this
sequence
(constructions
must
be
left)
.
2
a
Using
a
calculator,
complete
the
table
below,
giving
values
approximated
to
the
nearest
tenth
:
n
0
1
2
3
4
5
6
7
8
9
u
n
2.5
0.25
1.38
0.81
1.09
b
What
conjecture
can
be
made
about
the
limit
of
the
sequence
u
n
?
E.3412
Consider
the
sequence
u
n
n
∈
N
defined
by
the
recurrence
relation:
u
0
=
−
1
;
u
n
+1
=
f
u
n
for
all
n
∈
N
where
the
function
f
is
defined
by:
f
(
x
)=
x
2
+7
·
x
+14
2
·
x
+3
The
graph
below
represents,
in
an
orthonormal
coordinate
system
O
;
I
;
J
,
the
curve
C
f
representing
the
function
f
.
1
Graphically
represent
the
first
five
terms
of
this
sequence
on
the
x-axis
(the
constructions
must
be
left)
.
2
a
Using
a
calculator,
complete
the
table
below
by
indi-cating
the
values
of
the
terms
rounded
to
two
decimal
places.
n
0
1
2
3
4
5
u
n
−
1
2
3
;
2
3
;
76
4
;
03
n
6
7
8
9
10
11
u
n
b
What
conjecture
can
be
made
about
the
limit
of
the
terms
of
the
sequence
u
n
?
6.
With
a
spreadsheet
https://chingmath.fr
-4-3-2-1234I-4-3-2-123JOCf
chapExoCorrec/3411
sacados/3411
23I2JO(d
chapExoCorrec/3412
sacados/3412
-3-2-123456I23456JOCf
123456ABCDExnynwntn1128,339,258,949,029,009,009,009,00
1234567ABxnyn-34-4,81,4-4,681,76-2,688-4,2160,3792-4,98563,29472-3,76096
E.6732
Use
the
calculator
to
complete
the
ta-ble
of
values
for
each
of
the
following
sequences.
If
necessary,
round
the
values
to
the
nearest
hundredth
:
1
Let
u
n
be
defined
by
the
relation:
u
n
=
2
·
n
+
3
for
any
n
∈
N
n
0
1
2
3
4
5
6
7
u
n
2
Let
v
n
be
defined
by
the
relation:
v
0
=
5
;
v
n
+1
=
0.75
·
v
n
+
3
for
any
n
∈
N
Let
w
n
be
defined
by
the
relation:
w
n
=
v
n
−
12
for
any
n
∈
N
a
Complete
the
table
of
values
:
n
0
1
2
3
4
5
6
7
v
n
w
n
b
Verify
that
the
8
terms
of
the
sequence
w
n
allow
us
to
conjecture
that
the
sequence
w
n
is
geometric.
3
Let
t
n
be
defined
by
the
relationship
:
t
0
=0
;
t
1
=1
;
t
n
+1
=
t
n
+
t
n
−
1
for
all
n
∈
N
n
0
1
2
3
4
5
6
7
t
n
4
Let
a
n
and
b
n
be
defined
by
the
relations
:
a
0
=2
b
0
=
−
1
;
a
n
+1
=2
·
a
n
−
b
n
b
n
+1
=
a
n
+3
·
b
n
for
any
n
∈
N
n
0
1
2
3
4
5
6
7
a
n
b
n
E.6731
We
define
the
two
sequences
u
and
v
by:
u
0
=
1
v
0
=
12
;
u
n
+1
=
1
3
·
u
n
+2
·
v
n
v
n
+1
=
1
4
·
u
n
+3
·
v
n
for
any
n
∈
N
1
Using
a
spreadsheet,
generate
the
first
20
terms
of
these
two
sequences
to
obtain
a
table
sim-ilar
to
the
one
shown
opposite.
2
We
define
the
sequence
w
n
by:
w
n
=
v
n
−
u
n
a
In
the
column
C
,
express
the
first
20
terms
of
the
sequence
w
.
b
What
can
be
done
to
demonstrate
that
the
sequence
w
follows
a
geometric
progression
over
its
first
20
terms?
2
We
define
the
sequence
t
defined
by:
t
n
=3
·
u
n
+8
·
v
n
a
Express
the
first
20
terms
of
the
sequence
t
.
b
What
conjecture
can
be
made
about
the
nature
of
the
sequence
t
?
E.6722
Consider
the
two
sequences
x
n
and
y
n
jointly
defined
by
the
relations
:
x
0
=
−
3
y
0
=
4
et
x
n
+1
=
0.8
·
x
n
−
0.6
·
y
n
y
n
+1
=
0.6
·
x
n
+
0.8
·
y
n
for
all
n
∈
N
1
Using
a
spreadsheet,
generate
the
first
100
terms
of
the
sequence
in
a
table
similar
to
the
one
shown
oppo-site.
2
Use
the
graphics
tool,
selecting
the
range
A2:B101
to
represent
in
the
plane
the
points
M
n
defined
by
M
n
(
x
n
;
y
n
)
.
The
representation
mode
ˇ
XY
(dis-persion)
ı
will
be
chosen.
3
a
What
conjecture
can
be
made
about
the
position
of
the
sequence
of
points
M
n
in
the
plane?
b
Verify
that
the
point
M
0
verifies
this
conjecture.
c
Establish
the
relationship
:
OM
n
+1
=
OM
n
d
Complete
the
following
sentence
:
ˇ
If,
for
any
natural
number,
the
terms
of
a
se-quence
verify
the
relation
u
n
+1
=
u
n
then
the
se-quence
is
.
.
.
.
.
.
.
.
.
ı
7.
Arithmetic-geometric
sequences
E.6733
Consider
the
sequence
u
n
defined
by
the
relation:
u
0
=
8
;
u
n
+1
=
0.95
·
u
n
+
0.5
for
any
n
∈
N
1
We
define
the
sequence
v
n
defined
by
the
relation:
v
n
=
u
n
−
10
for
all
n
∈
N
a
Justify
that
the
sequence
v
n
is
a
geometric
sequence
of
reason
0.95
.
Specify
the
value
of
its
first
term.
b
Express
the
terms
of
the
sequence
v
n
as
a
function
of
n
.
2
Deduce
an
expression
for
the
sequence
u
n
as
a
function
of
n
3
Determine
the
limit
of
the
terms
of
the
sequence
u
n
when
n
tends
to
+
∞
.
https://chingmath.fr
chapExoCorrec/6732
sacados/6732
chapExoCorrec/6731
sacados/6731
123456ABCDExnynwntn1128,339,258,949,029,009,009,009,00
chapExoCorrec/6722
sacados/6722
1234567ABxnyn-34-4,81,4-4,681,76-2,688-4,2160,3792-4,98563,29472-3,76096
chapExoCorrec/6733
sacados/6733
E.6734
Consider
the
sequence
u
n
defined
by
the
relation:
u
0
=
−
2
;
u
n
+1
=
2
·
u
n
+
0.5
for
any
n
∈
N
1
We
define
the
sequence
v
n
defined
by
the
relation:
v
n
=
u
n
+
0.5
for
all
n
∈
N
a
Justify
that
the
sequence
v
n
is
a
geometric
sequence
whose
characteristic
elements
will
be
specified
b
Express
the
terms
of
the
sequence
v
n
as
a
function
of
n
.
2
Deduce
an
expression
for
the
sequence
u
n
as
a
function
of
n
3
Determine
the
limit
of
the
terms
of
the
sequence
u
n
when
n
tends
to
+
∞
.
E.3399
We
wish
to
study
the
sequence
(
u
n
)
of
first
term
u
0
=5
defined
by
the
following
recurrence
relation:
u
n
+1
=
1
3
u
n
+
4
for
all
n
∈
N
We
define
the
sequence
v
n
by:
v
n
=
u
n
−
6
for
all
n
∈
N
1
Show
that
the
sequence
(
v
n
)
is
a
geometric
sequence
whose
first
term
and
reason
will
be
specified.
2
Express
v
n
as
a
function
of
rank
n
.
3
Deduce
the
expression
of
u
n
as
a
function
of
n
.
4
Deduce
the
limit
of
the
sequence
u
n
.
E.5740
Consider
the
sequence
u
n
)
de-fined
on
N
∗
by:
u
1
=
0
;
u
n
+1
=
0.2
·
u
n
+
0.04
for
all
n
∈
N
∗
We
admit
that
for
any
natural
number:
u
n
<
0.05
We
define
the
sequence
v
n
on
N
∗
by
the
relation:
v
n
=
u
n
−
0.05
1
Show
that
the
sequence
v
n
is
a
geometric
sequence
whose
reason
will
be
specified.
2
Determine
the
expression
of
the
terms
of
the
sequence
v
n
as
a
function
of
n
.
Deduce
the
expression
of
the
terms
of
the
sequence
u
n
as
a
function
of
n
.
3
Deduce
the
limit
of
the
sequence
u
n
.
8.
Jointly
defined
sequences
E.6739
Consider
the
two
sequences
u
n
and
v
n
jointly
defined
by
the
following
relationships
:
u
0
=
5
v
0
=
4
;
u
n
+1
=
2
·
u
n
−
v
n
v
n
+1
=
−
3
·
u
n
+
4
·
v
n
for
any
n
∈
N
1
Consider
the
sequence
w
n
defined
by
the
relation:
w
n
=
v
n
−
u
n
for
all
n
∈
N
a
Establish
that
the
sequence
w
n
is
a
geometric
se-quence
of
reason
5
.
b
Deduce
that,
for
any
natural
number
n
,
the
term
of
rank
n
is
expressed
as
:
w
n
=
−
5
n
2
Consider
the
sequence
t
n
defined
by:
t
n
=
3
·
u
n
+
v
n
a
Show
that
:
t
0
=19
b
Establish
that
for
any
natural
number,
we
have
equal-ity:
t
n
+1
=
t
n
for
any
n
∈
N
We
will
admit
that,
for
any
n
∈
N
,
we
have
:
t
n
=19
3
Deduce
an
expression
for
the
terms
of
the
sequences
u
n
and
v
n
as
a
function
of
n
.
4
Deduce
the
limits
of
the
sequences
u
n
and
v
n
.
E.6738
Consider
the
two
sequences
u
n
and
v
n
jointly
defined
by
the
following
relations
:
u
0
=
3
v
0
=
−
1
;
u
n
+1
=
3
·
u
n
−
2
·
v
n
v
n
+1
=
−
u
n
+
2
·
v
n
1
Consider
the
sequence
w
n
defined
by
the
relation:
w
n
=
v
n
−
u
n
for
all
n
∈
N
a
Establish
that
the
sequence
w
n
is
a
geometric
se-quence
of
reason
4
.
b
Deduce
that,
for
any
natural
number
n
,
the
term
of
rank
n
is
expressed
as
:
w
n
=
−
4
×
4
n
2
Consider
the
sequence
t
n
defined
by:
t
n
=
4
·
u
n
+
8
·
v
n
for
any
n
∈
N
a
Give
the
value
of
the
term
t
0
.
b
Establish
that
for
any
natural
number,
we
have
the
equality:
t
n
+1
=
t
n
We’ll
admit
that
the
sequence
t
n
is
constant.
3
Deduce
an
expression
for
the
terms
of
the
sequences
u
n
and
v
n
as
a
function
of
n
.
4
Deduce
the
limits
of
the
sequences
u
n
and
v
n
.
https://chingmath.fr
chapExoCorrec/6734
sacados/6734
chapExoCorrec/3399
sacados/3399
chapExoCorrec/5740
sacados/5740
chapExoCorrec/6739
sacados/6739
chapExoCorrec/6738
sacados/6738
E.3414
Consider
the
two
sequences
p
n
n
∈
N
and
q
n
n
∈
N
whose
first
terms
are:
p
0
=5
;
q
0
=
2
They
are
defined
by
the
following
recurrence
relations
:
p
n
+1
=
0.5
·
p
n
+
0.4
·
q
n
;
q
n
+1
=
0.4
·
p
n
+
0.5
·
q
n
We
define
the
sequences
u
n
n
∈
N
and
v
n
n
∈
N
by
the
follow-ing
relations
:
u
n
=
q
n
+
p
n
;
v
n
=
p
n
−
q
n
1
Determine
the
exact
value
of
the
first
three
terms
of
each
of
the
sequences
u
n
and
v
n
.
2
a
Show
that
the
sequence
u
n
is
a
geometric
sequence
of
reason
0.9
.
b
Deduce
the
limit
of
the
sequence
u
n
.
3
Determine
the
limit
of
the
sequence
v
n
.
4
a
Noting
that
u
n
+
v
n
=2
·
p
n
,
deduce
that
the
sequence
p
n
is
convergent
;
specify
its
limit.
b
Establish
that
the
sequence
q
n
is
convergent
;
deter-mine
its
limit.
E.6759
Consider
the
sequences
a
n
and
b
n
defined
by:
a
0
=
6
b
0
=
1
a
n
+1
=
0.2
·
a
n
+
1.3
·
b
n
b
n
+1
=
−
0.8
·
a
n
−
0.2
·
b
n
for
any
n
∈
N
1
Express
the
terms
a
n
+2
and
b
n
+2
in
terms
of
a
n
and
b
n
.
2
What
can
be
said
about
the
terms
of
the
sequence
a
2
n
?
E.6758
Consider
the
sequences
a
n
and
b
n
defined
by:
a
0
=
2
b
0
=
1
;
a
n
+1
=
0.8
·
a
n
+
0.9
·
b
n
b
n
+1
=
0.4
·
a
n
−
0.8
·
b
n
∀
n
∈
N
1
Establish
the
equalities:
a
n
+2
=
a
n
;
b
n
+2
=
b
n
2
What
can
we
say
about
the
limits
of
the
sequences
a
n
and
b
n
?
9.
Other
suites
E.6765
Let
u
n
be
the
sequence
defined
by
its
first
term
u
0
=5
and,
for
any
natural
number
n
by:
u
n
+1
=
0.5
·
u
n
+
0.5
·
n
−
1.5
1
Let
v
n
be
the
sequence
defined
for
any
natural
number
n
by:
v
n
=
0.1
·
u
n
−
0.1
·
n
+
0.5
Show
that
the
sequence
v
n
is
geometric
of
reason
0.5
and
then
express
v
n
as
a
function
of
n
.
2
Deduce
that,
for
any
natural
number
n
:
u
n
=
10
×
0.5
n
+
n
−
5
3
Then
determine
the
limit
of
the
sequence
u
n
E.6799
Consider
the
sequence
u
n
defined
by:
u
0
=
6
;
u
n
+1
=
2
·
u
n
−
3
·
n
+
5
for
all
n
∈
N
1
Give
the
first
three
terms
of
the
sequence
u
n
.
2
Consider
the
sequence
v
n
defined
by:
v
n
=
u
n
−
3
·
n
+
2
a
Demonstrate
that
the
sequence
v
n
is
a
geometric
se-quence
of
reason
2
.
b
Deduce
an
expression
for
the
terms
of
the
sequence
v
n
as
a
function
of
their
rank.
3
a
Justify
that
for
any
natural
number
n
,
we
have
:
u
n
=
8
×
2
n
+
3
·
n
−
2
b
Deduce
the
limit
of
suite
u
n
.
E.5737
Let
the
numerical
sequence
u
n
be
defined
on
N
by:
u
0
=
2
;
u
n
+1
=
2
3
·
u
n
+
1
3
·
n
+
1
for
all
n
∈
N
We
denote
by
v
n
the
sequence
defined
on
N
by:
v
n
=
u
n
−
n
1
Demonstrate
that
the
sequence
v
n
is
a
geometric
se-quence
of
reason
2
3
.
2
Deduce
that
for
any
natural
number
n
:
u
n
=
2
·
2
3
n
+
n
3
Determine
the
limit
of
the
sequence
u
n
.
E.2620
Consider
the
sequence
u
n
n
∈
N
whose
first
term
is
0
defined
by
the
following
recurrence
relation:
u
n
+1
=
2
5
·
u
n
−
3
·
n
−
8
pour
tout
n
∈
N
1
Determine
the
first
three
terms
of
this
sequence.
2
Consider
the
sequence
v
n
n
∈
N
defined
by
the
relation:
v
n
=
u
n
+
5
n
+
5
for
all
n
∈
N
a
Show
that
the
sequence
v
n
is
a
geometric
sequence
whose
reason
and
first
term
will
be
specified.
b
Deduce
the
explicit
formula
for
the
sequence
u
n
of
a
term
as
a
function
of
n
its
rank.
3
Deduce
the
limit
of
the
sequence
u
n
.
https://chingmath.fr
chapExoCorrec/3414
sacados/3414
chapExoCorrec/6759
sacados/6759
chapExoCorrec/6758
sacados/6758
chapExoCorrec/6765
sacados/6765
chapExoCorrec/6799
sacados/6799
chapExoCorrec/5737
sacados/5737
chapExoCorrec/2620
sacados/2620
E.3285
We
define
the
sequence
u
n
is
defined
by:
u
0
=
1
;
u
n
+1
=
1
2
u
n
+
n
−
1
for
all
n
∈
N
We
define
the
sequence
(
v
n
)
by:
v
n
=4
u
n
−
8
n
+24
1
By
successive
transformation,
establish
the
following
equality:
v
n
+1
=
1
2
·
v
n
.
2
Deduce
an
expression
for
the
terms
of
the
sequence
u
n
as
a
function
of
n
.
E.3518
Consider
the
numerical
sequence
u
defined
by:
u
0
=
1
;
u
n
+1
=
1
3
·
u
n
+
n
−
1
for
any
natural
number
n
.
Let
v
be
the
sequence
defined
for
any
integer
ntaturel,
by:
v
n
=
4
·
u
n
−
6
n
+
15
1
Show
that
v
is
a
geometric
sequence.
2
Calculate
v
0
,
then
calculate
v
n
as
a
function
of
n
.
Deduce
that
for
any
natural
number
n
:
u
n
=
19
4
×
1
3
n
+
6
n
−
15
4
3
Show
that
the
sequence
u
can
be
written
as
:
u
=
t
+
w
où
t
is
a
geometric
sequence
w
a
sequence
arithmétique
4
Calculate
the
value
of
the
two
sums
:
T
n
=
t
0
+
t
1
+
·
·
·
+
t
n
;
W
n
=
w
0
+
w
1
+
·
·
·
+
w
n
.
Deduct
:
U
n
=
u
0
+
u
1
+
···
+
u
n
.
10.
Other
sequences:
linear
recurrent
sequences
of
order
2
E.3515
Consider
the
sequence
u
n
n
∈
N
defined
by:
u
0
=
0
u
1
=
1
;
u
n
+1
=
7
·
u
n
+
8
·
u
n
−
1
pour
tout
n
∈
N
1
Determine
the
value
of
the
first
five
terms
of
the
sequence
u
n
.
2
Show
that
the
sequence
s
n
n
∈
N
defined
by:
s
n
=
u
n
+1
+
u
n
pour
tout
n
∈
N
is
a
geometric
sequence
whose
reason
will
be
specified.
Deduce
s
n
as
a
function
of
n
.
3
a
We
pose
v
n
=(
−
1)
n
·
u
n
and
consider
the
sequence
t
n
n
∈
N
defined
by:
t
n
=
v
n
+1
−
v
n
for
all
n
∈
N
Express
t
n
as
a
function
of
s
n
.
b
What
is
the
nature
of
the
sequence
t
n
.
4
a
Express
v
n
,
then
u
n
,
as
a
function
of
n
(we
can
cal-culate,
in
two
ways,
the
sum
t
0
+
···
+
t
n
−
1
)
.
b
Determine
:
lim
n
↦→
+
∞
u
n
8
n
.
E.3421
Consider
the
set
(
E
)
of
the
se-
quences
x
n
defined
on
N
and
verifying
the
following
rela-tion
:
for
any
non-zero
natural
number
n
,
x
n
+1
−
x
n
=0.24
·
x
n
−
1
1
Consider
a
non-zero
real
–
and
define
on
N
the
sequence
t
n
by
t
n
=
–
n
.
Show
that
the
sequence
t
n
belongs
to
the
set
(
E
)
if,
and
only
if,
–
is
a
solution
of
the
equation
:
–
2
−
–
−
0.24
=
0
Deduce
the
sequences
t
n
belonging
to
the
set
(
E
)
.
Let
(
E
)
be
the
set
of
sequences
u
n
defined
on
N
by
a
rela-tion
of
the
form
:
u
n
=
¸
·
(1.2)
n
+
˛
·
(
−
0.2)
n
¸
and
˛
are
real
numbers.
2
Consider
a
sequence
u
n
of
the
set
(
E
)
.
Determine
the
values
of
¸
and
˛
such
that
:
u
0
=
6
and
u
1
=
6.6
Deduce
that,
for
any
natural
number
n
:
u
n
=
39
7
·
(1.2)
n
+
3
7
·
(
−
0.2)
n
.
3
Determine
:
lim
n
↦→
+
∞
u
n
.
11.
Limits
of
explicitly
defined
sequences
E.2558
Determine
the
limits
of
the
sequences
u
n
defined
below
:
a
n
3
×
5
n
b
n
−
2
7
n
c
1
3
n
−
3
2
n
d
8
n
−
3
n
e
5
n
−
2
n
3
n
+
2
n
f
31
7
n
·
2
8
n
E.3104
In
each
case,
determine
the
limit
of
the
sequence
u
n
whose
general
term
as
a
function
of
n
is
given
below
a
n
5
×
3
n
2
3
b
5
n
−
8
n
c
2
3
n
·
4
3
n
+2
d
3
n
−
2
n
5
n
−
4
n
12.
Gendarme
theorems
https://chingmath.fr
chapExoCorrec/3285
sacados/3285
chapExoCorrec/3518
sacados/3518
chapExoCorrec/3515
sacados/3515
chapExoCorrec/3421
sacados/3421
chapExoCorrec/2558
sacados/2558
chapExoCorrec/3104
sacados/3104
E.2554
Consider
the
sequence
u
n
n
∈
N
de-fined,
for
any
natural
number
n
,
by
the
explicit
relation:
u
n
=
3
n
+(
−
1)
n
2
n
−
1
1
Determine
the
first
three
terms
of
the
sequence
u
n
.
2
Establish
the
following
frame
:
For
any
n
∈
N
∗
:
3
n
−
1
2
n
−
1
u
n
3
n
+1
2
n
−
1
3
Deduce
the
convergence
value
of
u
n
.
E.2567
Let
u
n
n
∈
N
be
defined
by
the
explicit
formula
of
its
rank
term
n
:
u
n
=
2
·
n
+
1
−
2
·
n
1
Show
the
following
equality
for
any
n
∈
N
:
u
n
=
1
2
·
n
+
1
+
2
·
n
2
For
any
non-zero
natural
number
n
,
establish
the
follow-ing
frame
:
0
<u
n
<
1
2
·
√
2
·
n
3
Deduce
the
limit
of
the
sequence
u
n
.
E.3441
Consider
the
sequence
u
n
n
∈
N
∗
whose
rank
term
n
is
defined
by
the
relation:
u
n
=
1
n
+
1
+
1
n
+
2
+
·
·
·
+
1
n
+
n
1
Establish
the
following
frame
for
any
non-zero
natural
number
n
:
n
n
+
n
u
n
n
n
+
1
2
Deduce
the
convergence
of
the
sequence
u
n
;
specify
the
value
of
the
limit.
E.2587
Consider
the
sequence
u
n
n
∈
N
∗
is
de-fined
explicitly
by
the
formula
:
u
n
=
3
4
n
2
+
1
+
3
4
n
2
+
2
+
·
·
·
+
3
4
n
2
+
n
1
Compare
the
following
two
terms
:
3
4
n
2
+
1
and
3
4
n
2
+
n
2
Establish
that
the
sequence
u
n
converges
to
3
2
.
13.
Lesson
-
Sequences
E.5741
Let
‘
be
a
real
number.
Consider
a
se-quence
u
n
that
converges
to
‘
then
the
real
‘
to
which
the
sequence
u
n
converges
is
unique.
E.3281
Prerequisite
:
definition
of
a
se-quence
tending
to
+
∞
.
ˇA
sequence
tends
to
+
∞
if,
for
any
real
A
,
all
the
terms
of
the
sequence
are,
from
a
certain
rank,
greater
than
A
ı
Prove
the
following
theorem
:
a
non-major
increasing
se-quence
tends
to
+
∞
E.5496
Consider
the
two
sequences
u
n
and
v
n
verifying:
There
exists
n
0
such
that
from
n
0
,
the
terms
of
the
two
sequences
:
n
n
0
=
⇒
v
n
u
n
lim
n
↦→
+
∞
u
n
=
+
∞
Establish
that
:
lim
n
↦→
+
∞
v
n
=
+
∞
E.5497
Consider
a
growing
sequence
u
n
.
If
the
sequence
u
n
converges
to
a
finite
limit
‘
then
all
terms
of
the
sequence
u
n
are
less
than
or
equal
to
‘
.
14.
Unclassified
financial
years
E.5570
Consider
the
numerical
sequence
v
n
defined
for
any
natural
number
n
by:
v
0
=
1
;
v
n
+1
=
9
6
−
v
n
for
any
integer
n
∈
N
Consider
the
sequence
w
n
defined
by:
w
n
=
1
v
n
−
3
for
any
natural
number
n
.
1
Demonstrate
that
w
n
is
an
arithmetic
sequence
of
rea-son
−
1
3
and
first
term
−
1
2
2
a
Determine
the
expression
of
the
terms
of
the
se-quence
w
n
as
a
function
of
rank
n
.
b
Deduce
the
expression
of
the
terms
of
the
sequence
v
n
as
a
function
of
rank
n
.
(we
will
not
simplify
the
expression
of
v
n
)
.
3
Determine
the
limit
of
the
sequence
v
n
.
E.4012
Consider
the
sequence
of
real
num-bers
u
n
defined
on
N
by:
u
0
=
−
1
;
u
1
=
1
2
;
u
n
+2
=
u
n
+1
−
1
4
·
u
n
for
all
n
∈
N
1
Calculate
u
2
and
deduce
that
the
sequence
u
n
is
nei-ther
arithmetic
nor
geometric.
2
We
define
the
sequence
v
n
by
posing
:
v
n
=
u
n
+1
−
1
2
·
u
n
for
all
n
∈
N
a
Calculate
v
0
.
b
Establish
that
v
n
is
geometric
of
reason
1
2
.
c
Express
v
n
in
terms
of
n
.
https://chingmath.fr
chapExoCorrec/2554
sacados/2554
chapExoCorrec/2567
sacados/2567
chapExoCorrec/3441
sacados/3441
chapExoCorrec/2587
sacados/2587
chapExoCorrec/5741
sacados/5741
chapExoCorrec/3281
sacados/3281
chapExoCorrec/5496
sacados/5496
chapExoCorrec/5497
sacados/5497
chapExoCorrec/5570
sacados/5570
Extrait Liban
2013
chapExoCorrec/4012
sacados/4012
Extrait Antilles-Guyane
Septembre 2010
E.4225
Peter
and
Claude
play
tennis.
Both
players
have
the
same
chance
of
winning
the
first
game.
Thereafter,
when
Peter
wins
a
game,
the
probability
that
he
wins
the
next
is
0.7
.
And
if
he
loses
one
game,
the
probability
that
he
will
lose
the
next
is
0.8
.
Throughout
the
exercise,
n
is
a
non-zero
natural
number.
Consider
the
events
:
G
n
:
ˇ
Pierre
wins
the
n
-game.
ı
P
n
:
ˇ
Pierre
loses
the
n
-th
game.
ı
We
pose
:
p
n
=
P
(
G
n
)
;
q
n
=
P
(
P
n
)
Finding
a
recurrence
relation
:
1
Determine
p
1
then
the
conditional
probabilities
:
P
G
1
(
G
2
)
;
P
P
1
(
G
2
)
.
2
Justify
the
equality:
p
n
+
q
n
=1
.
3
Demonstrate
that
for
any
non-zero
natural
number
n
:
p
n
+1
=
0.5
·
p
n
+
0.2
.
E.2555
Determine
the
limits
of
the
sequences
u
n
n
∈
N
below
defined
explicitly:
a
u
n
=
2
n
2
−
3
n
+
1
n
+
1
b
u
n
=
n
−
3
n
2
+
1
c
u
n
=
2
n
+
1
n
+
1
d
u
n
=
1
+
n
−
2
n
2
+
3
n
3
E.6176
Determine
the
value
of
the
following
limits:
a
lim
n
↦→
+
∞
n
2
+
2
b
lim
n
↦→
+
∞
2
+
1
n
c
lim
n
↦→
+
∞
n
3
+
n
+
2
d
lim
n
↦→
+
∞
n
−
1
n
e
lim
n
↦→
+
∞
n
·
n
−
10
f
lim
n
↦→
+
∞
1
+
1
n
n
+
1
E.6177
Determine
the
value
of
the
following
limits:
a
lim
n
↦→
+
∞
n
2
−
n
b
lim
n
↦→
+
∞
n
2
+
n
+
1
n
c
lim
n
↦→
+
∞
1
n
2
+
1
n
d
lim
n
↦→
+
∞
n
n
2
+
n
+
1
e
lim
n
↦→
+
∞
2
n
2
+
n
+
1
n
−
2
f
lim
n
↦→
+
∞
n
2
−
1
n
https://chingmath.fr
chapExoCorrec/4225
sacados/4225
Extrait d'Asie
Juin 2006
chapExoCorrec/2555
sacados/2555
chapExoCorrec/6176
sacados/6176
chapExoCorrec/6177
sacados/6177