Grade 11
/ Study of sequences 66 exercises (including 58 corrected)
-2-1234I-12JOCf
-4-3-2-1234I-3-2-123JOCf
E.2378
Consider
the
function
f
defined
on
[
−
2
;
4]
whose
representative
curve
C
f
is
given
below
:
Consider
the
sequence
u
n
n
∈
N
defined
by
the
relation
u
0
=
3
;
u
n
+1
=
f
u
n
for
all
n
∈
N
1
Complete
the
following
table
with
the
first
terms
of
the
sequence
u
n
:
n
0
1
2
3
4
5
6
7
8
9
u
n
2
For
each
of
the
statements
below,
state
whether
they
are
true
or
false
:
ˇ
the
sequence
u
n
is
strictly
decreasing
on
N
.
ı
ˇ
the
sequence
u
n
is
constant
from
rank
3
.
ı
E.8478
1
Consider
the
sequence
u
n
defined
for
any
natural
num-ber
n
(
n
∈
N
)
by:
u
0
=2
;
u
n
+1
=
1
2
·
u
n
−
1
4
a
Determine
the
4
first
terms
of
the
suite
u
n
.
b
Conjecture
the
variation
of
the
sequence
u
n
2
Consider
the
sequence
v
n
defined
for
any
natural
num-ber
n
(
n
∈
N
)
by:
v
0
=
−
1
;
v
n
+1
=
1
2
·
v
n
−
1
4
a
Justify
comparisons
:
v
0
<v
1
<v
2
<v
3
b
Conjecture
the
variation
of
the
sequence
v
n
E.8479
Consider
the
sequence
u
n
defined
for
any
natural
number
n
(
n
∈
N
)
by:
u
0
=
1
;
u
n
+1
=
2
1
+
2
u
n
1
Determine
the
first
5
terms
of
the
suite
u
n
.
2
Conjecture
the
direction
of
variations
of
the
sequence
u
n
.
3
Conjecture
the
explicit
expression
of
the
general
term
of
the
sequence
u
n
as
a
function
of
its
rank
n
.
4.
Variations:
constant
or
periodic
sequences
E.2978
In
the
plane
provided
with
an
or-thonormal
reference
frame
O
;
I
;
J
,
consider
the
representa-tion
C
f
of
a
function
f
defined
on
the
interval
[
−
4
;
4]
:
1
Consider
the
sequence
(
u
n
)
defined
for
any
natural
num-ber
n
(
n
∈
N
)
defined
by:
u
0
=
4
;
u
n
+1
=
f
u
n
a
Determine
the
value
of
the
first
6
terms
of
the
suite
u
n
.
b
Determine
the
value
of
term
u
100
.
2
Consider
the
sequence
(
v
n
)
defined
for
any
natural
num-ber
n
(
n
∈
N
)
defined
by:
v
0
=
−
2
;
v
n
+1
=
f
v
n
Determine
the
value
of
the
term
v
100
.
E.2953
Consider
the
sequence
u
n
n
∈
N
de-fined
by
the
following
recurrence
relation:
u
0
=
3
;
u
n
+1
=
1
−
u
n
1
+
u
n
for
all
n
∈
N
1
Determine
the
first
five
terms
of
the
sequence
u
n
.
2
Show
that
we
have
the
following
relationship
:
u
n
+2
=
u
n
for
all
n
∈
N
3
What
can
be
said
about
the
terms
of
this
sequence?
4
We
admit
that
the
term
of
rank
n
of
the
sequence
u
n
admits
an
expression
of
the
form
:
u
n
=
a
·
1
−
(
−
1)
n
+
b
pour
tout
n
∈
N
where
a
and
b
are
two
real
numbers
(
a;b
∈
R
)
.
Determine
the
values
of
a
and
b
.
5.
Variations:
explicit
sequences
https://chingmath.fr
chapExoCorrec/2378
sacados/2378
-2-1234I-12JOCf
chapExoCorrec/8478
sacados/8478
chapExoCorrec/8479
sacados/8479
chapExoCorrec/2978
sacados/2978
-4-3-2-1234I-3-2-123JOCf
chapExoCorrec/2953
sacados/2953
unest croissanteunest décroissanteu0>0etr>0u0>0etr<0u0<0etr>0u0<0etr<0
E.8485
The
sequence
u
n
n
∈
N
is
de-fined
by:
u
n
=
−
2
·
n
2
−
3
·
n
+
2
for
all
n
∈
N
Study
the
monotonicity
of
each
of
the
sequences
below,
by
studying
the
function
f
verifying
the
relation:
u
n
=
f
(
n
)
for
all
n
∈
N
E.2386
Consider
the
sequence
u
n
n
∈
N
whose
term
of
rank
n
is
given
by
the
formula
:
u
n
=
n
2
−
7
·
n
+
1
1
Using
the
calculator,
complete
the
table
below
:
n
0
1
2
3
4
5
6
7
8
9
10
u
n
2
After
giving
the
table
of
variations
of
the
function
f
whose
image
of
x
is
defined
by:
f
(
x
)
=
x
2
−
7
·
x
+
1
Establish
that
the
sequence
u
n
is
increasing
from
rank
4.
6.
Variations:
explicit
sequences
with
derivatives
E.2382
The
sequence
u
n
is
defined
by:
u
n
=
2
·
n
2
+1
2
·
n
+5
for
all
n
∈
N
Consider
the
function
f
defined
by:
f
(
x
)
=
2
·
x
2
+
1
2
·
x
+
5
1
Give
the
defining
set
D
f
of
the
function
f
.
2
Establish
that
the
function
f
derived
from
the
function
f
admits
as
expression
on
D
f
:
f
(
x
)
=
4
·
x
2
+
20
·
x
−
2
(2
·
x
+
5)
2
3
Draw
up
the
table
of
variations
of
the
function
f
.
4
Justify
that
the
sequence
u
n
is
increasing
from
rank
1
.
5
Can
we
say
that
the
sequence
u
n
is
increasing
on
N
?
E.2410
Establish
the
monotonicity
on
N
of
the
sequence
u
n
n
∈
N
defined
by
the
explicit
formula
:
u
n
=
n
2
−
1
√
n
for
all
n
∈
N
.
7.
Variations
of
arithmetic
sequences
E.10424
Consider
the
suite
u
n
arithmetic,
defined
for
any
n
∈
N
,
with
first
term
of
2
and
reason
3
:
1
Give
the
expression
of
the
terms
of
the
sequence
u
n
as
a
function
of
their
rank
n
.
2
For
n
∈
N
,
simplify
the
expression
u
n
+1
−
u
n
3
Deduce
the
direction
of
variation
of
the
sequence
u
n
.
Proposition:
let
u
n
be
an
arithmetic
sequence
:
u
n
is
strictly
decreasing
if,
and
only
if,
its
reason
is
strictly
negative
;
u
n
is
strictly
increasing
if,
and
only
if,
its
reason
is
strictly
positive
;
u
n
is
constant
if,
and
only
if,
its
reason
is
zero;
E.10425
Let
u
n
be
an
arithmetic
sequence
with
first
term
u
0
and
reason
r
.
1
Connect
the
corresponding
assertions
:
2
A
quelle
(s)
condition
(s)
arithmetic
sequence
is
constant?
E.8495
Let
u
n
n
∈
N
be
the
arithmetic
se-quence
of
first
term
1
and
reason
3
.
Justify
that
the
sequence
u
n
is
an
increasing
sequence
on
N
.
E.10423
Let
v
n
n
∈
N
be
the
sequence
defined
for
any
natural
number
n
(
n
∈
N
)
and
whose
term
of
rank
n
admits
the
expression
:
v
n
=
4
−
n
Justify
that
the
sequence
v
n
is
decreasing
on
N
.
E.2380
Let
u
n
n
∈
N
be
the
sequence
whose
rank
term
n
is
defined
by:
u
n
=
−
32
n
+
102
for
all
n
∈
N
Show
that
this
sequence
is
decreasing.
https://chingmath.fr
chapExoCorrec/8485
sacados/8485
fichierPlus/8485/diapoCorrection.pdf
chapExoCorrec/2386
sacados/2386
chapExoCorrec/2382
sacados/2382
fichierPlus/2382/
chapExoCorrec/2410
sacados/2410
sacados/10424
sacados/10425
unest croissanteunest décroissanteu0>0etr>0u0>0etr<0u0<0etr>0u0<0etr<0
chapExoCorrec/8495
sacados/8495
chapExoCorrec/10423
sacados/10423
chapExoCorrec/2380
sacados/2380
0<q<1qq>1u0<0u0u0>0
unest croissanteunest décroissanteu0>0etq>1u0>0et0<q<1u0>0et−1<q<0u0>0etq<−1u0<0etq>1u0<0et0<q<1u0<0et−1<q<0u0<0etq<−1
8.
Variations
of
geometric
sequences
E.10427
Consider
the
sequence
u
n
defined
for
all
n
∈
N
geometric
terms
with
first
term
3
and
common
ratio
0.1
.
1
Express
the
term
of
the
sequence
u
n
of
rank
n
in
terms
of
n
.
2
Simplify
and
factor
the
expression
u
n
+1
−
u
n
.
3
Deduce
the
direction
of
variation
of
the
sequence
u
n
.
Proposition:
Let
u
n
be
a
geometric
sequence
with
com-mon
ratio
q
.
If
u
0
>
0
and
q>
1
,
then
the
sequence
u
n
is
strictly
increasing.
If
q
=1
,
then
the
sequence
u
n
is
constant.
If
u
0
>
0
and
0
<q<
1
,
then
the
sequence
u
n
is
strictly
decreasing.
E.9846
Consider
the
suite
u
n
n
∈
N
geomet-ric
with
first
term
u
0
and
reason
q
.
In
the
table
below,
indicate
the
direction
of
variation
of
the
sequence
u
n
as
a
function
of
the
value
of
its
characteristic
elements
:
E.10426
Let
u
n
be
a
geometric
sequence
with
first
term
u
0
and
reason
r
.
1
Connect
the
corresponding
assertions
:
2
A
quelle
(s)
condition
(s)
geometric
sequence
is
constant?
9.
Variations:
difference
between
consecutive
terms
E.8480
Consider
the
sequence
u
n
defined
by:
u
n
=
1
−
n
1
+
n
for
all
n
∈
N
1
Determine
a
simplified
expression
for
u
n
+1
−
u
n
.
2
Deduce
the
variations
of
the
sequence
u
n
on
N
.
E.8482
Consider
the
sequence
u
n
defined
by
the
relation:
u
n
=
n
3
−
4
·
n
2
+
n
−
3
for
all
n
∈
N
1
Establish
the
identity
below
for
any
natural
number
n
:
u
n
+1
−
u
n
=
3
·
n
2
−
5
·
n
−
2
.
2
Deduce
that
the
sequence
u
n
is
increasing
from
rank
2
.
E.8481
Let
u
n
n
∈
N
be
defined
by
the
ex-plicit
relation:
u
n
=
n
3
−
2
n
2
−
3
n
1
Give
the
simplified
expression
of
:
u
n
+1
−
u
n
.
2
Deduce
that
the
sequence
(
u
n
)
is
increasing
for
n
greater
than
2.
E.3401
Consider
the
sequence
u
n
defined
by:
u
n
=
n
2
+
10
2
·
n
for
any
n
∈
N
∗
Justify
that
u
n
is
increasing
from
rank
3
.
E.6040
Consider
the
sequence
u
n
defined
on
N
defined
by:
u
n
=
5
n
−
1
(
n
+
1)
2
1
Give
the
simplified
and
factorized
form
of
the
difference
:
u
n
+1
−
u
n
2
Justify
that
the
sequence
u
n
is
decreasing
from
rank
1
.
https://chingmath.fr
sacados/10427
chapExoCorrec/9846
sacados/9846
0<q<1qq>1u0<0u0u0>0
sacados/10426
unest croissanteunest décroissanteu0>0etq>1u0>0et0<q<1u0>0et−1<q<0u0>0etq<−1u0<0etq>1u0<0et0<q<1u0<0et−1<q<0u0<0etq<−1
chapExoCorrec/8480
sacados/8480
chapExoCorrec/8482
sacados/8482
chapExoCorrec/8481
sacados/8481
chapExoCorrec/3401
sacados/3401
chapExoCorrec/6040
sacados/6040
E.8496
Let
u
n
be
the
sequence
whose
rank
term
n
is
defined
by:
u
n
=
2
n
−
1
for
all
n
∈
N
∗
1
Establish
the
identity
below
for
any
strictly
positive
nat-ural
number
n
(
n
∈
N
∗
)
:
u
n
+1
−
u
n
=
2
2
n
+
1
+
2
n
−
1
2
deduce
that
the
suite
u
n
is
strictly
increasing
on
N
∗
.
E.8497
Let
w
n
be
the
sequence
whose
rank
term
n
is
defined
by:
w
n
=
2
n
−
25
n
for
all
n
∈
N
∗
Show
that
the
sequence
w
n
is
increasing.
E.8483
The
sequence
u
n
is
defined
by
the
explicit
formula
:
u
n
=
5
+
n
n
for
all
n
∈
N
∗
Determine
the
direction
of
variation
of
the
sequence
u
n
.
10.
Variations:
difference
of
consecutive
terms
(sequences
defined
by
recurrence)
E.5367
Let
u
n
n
∈
N
be
the
sequence
defined
by:
u
0
=
1
;
u
n
+1
=
u
n
−
u
n
2
−
1
for
all
n
∈
N
1
Complete
the
table
below
of
the
first
terms
of
the
se-quence
u
n
:
n
0
1
2
3
4
u
n
2
By
studying
the
difference
of
two
consecutive
terms,
show
that
the
sequence
u
n
is
decreasing.
E.10639
Consider
the
sequence
u
n
defined
on
N
by:
u
0
=
−
3
;
u
n
+1
=
u
n
−
3
n
+
7
1
Determine
the
first
four
terms
of
the
sequence
u
n
.
2
Determine
from
which
rank
the
sequence
u
n
is
decreas-ing.
11.
Variations:
quotient
of
consecutive
terms
E.8494
1
Let
u
n
be
the
geometric
sequence
defined
at
N
with
first
term
2
and
reason
4
.
Justify
that
the
sequence
u
n
is
increasing.
2
Let
v
n
be
the
sequence
defined
for
any
natural
number
n
(
n
∈
N
)
and
whose
term
of
rank
n
admits
the
expres-sion
:
v
n
=
3
×
0
;
2
n
Justify
that
the
sequence
v
n
is
decreasing.
E.2381
Consider
the
sequence
u
n
defined
by:
u
n
=
3
n
4
for
any
n
∈
N
.
Show
that
u
n
is
strictly
increasing.
E.2522
Consider
the
sequence
u
n
defined
for
any
natural
number
n
(
n
∈
N
)
by:
u
n
=
5
n
n
+
2
Show
that
the
sequence
u
n
n
∈
N
is
an
increasing
sequence
on
N
.
E.5491
Consider
the
sequence
u
n
defined
by:
u
n
=
3
n
2
n
+
1
for
all
n
∈
N
Determine
the
variations
of
the
sequence
u
n
on
N
.
E.10471
Consider
the
sequence
u
n
defined
on
N
by:
u
n
=
2
n
n
2
+
1
Determine
from
which
rank
the
sequence
u
n
is
increasing.
E.2451
The
sequence
u
n
is
defined
by
the
explicit
formula
:
u
n
=
2
n
3
·
n
for
all
n
∈
N
∗
Determine
the
direction
of
variation
of
the
sequence
u
n
.
12.
Variations
from
one
rank:
quotient
of
consecutive
terms
E.2450
Consider
the
sequence
u
n
defined
by
the
explicit
formula
:
u
n
=
1.2
n
n
for
any
n
∈
N
∗
.
1
Give
the
simplified
expression
of
u
n
+1
u
n
.
https://chingmath.fr
chapExoCorrec/8496
sacados/8496
chapExoCorrec/8497
sacados/8497
chapExoCorrec/8483
sacados/8483
chapExoCorrec/5367
sacados/5367
sacados/10639
chapExoCorrec/8494
sacados/8494
chapExoCorrec/2381
sacados/2381
chapExoCorrec/2522
sacados/2522
chapExoCorrec/5491
sacados/5491
sacados/10471
chapExoCorrec/2451
sacados/2451
chapExoCorrec/2450
sacados/2450
2
Show
that
u
n
is
increasing
from
rank
5
.
E.2670
Determine
the
direction
of
variation
of
the
sequence
u
n
defined
by
the
relation:
u
n
=
n
×
(0.4)
n
for
all
n
∈
N
∗
E.8490
We
record
the
sequence
u
n
n
∈
N
∗
defined
by
the
explicit
formula
:
u
n
=
1.2
n
n
2
for
all
n
∈
N
∗
.
1
Establish
the
following
identity
for
any
n
∈
N
∗
:
u
n
+1
u
n
−
1
=
n
2
−
10
·
n
−
5
5
·
(
n
+
1)
2
2
Deduce
that
the
sequence
u
n
is
increasing
from
rank
11
.
E.8489
The
sequence
u
n
n
∈
N
is
defined
by:
u
n
=
n
2
n
+1
for
all
n
∈
N
Show
that
u
n
is
strictly
decreasing
from
rank
2
.
13.
Link
between
recurring
formula
and
explicit
formula
E.2383
1
Consider
the
sequence
u
n
n
∈
N
whose
rank
term
n
is
de-fined
by
the
recurrence
relation:
u
0
=
2
;
u
n
+1
=
1
3
·
u
n
+
1
for
any
n
∈
N
Calculate
the
first
4
terms
of
the
sequence
u
n
.
2
Consider
the
sequence
v
n
n
∈
N
defined
explicitly
by:
v
n
=
1
2
·
1
3
n
+
3
2
a
Calculate
the
first
4
terms
of
the
sequence
v
n
b
Establish
that
for
any
natural
number
n
,
we
have
:
v
n
+1
−
1
3
·
v
n
=
1
3
Deduce
the
equality
of
the
sequences
u
n
and
v
n
.
E.2384
1
Let
u
n
n
∈
N
∗
,
the
sequence
defined
by
the
recurrence
re-lation
and
the
initial
condition
:
u
1
=
1
;
u
n
+1
=
1
1
+
1
u
n
for
any
n
∈
N
∗
Calculate
the
first
4
terms
of
the
sequence.
2
Let
v
n
n
∈
N
∗
be
the
sequence
whose
term
of
rank
n
has
the
value
:
v
n
=
1
n
for
all
n
∈
N
∗
a
Give
the
value
of
v
1
.
b
Establish
the
following
identity
for
any
n
∈
N
∗
:
1
+
1
v
n
=
n
+
1
c
Deduce
that
the
sequence
v
n
follows
the
recurrence
relation
below
for
any
non-zero
natural
number:
v
n
+1
=
1
1+
1
v
n
3
What
can
you
say
about
the
sequences
u
n
and
v
n
?
E.5136
Consider
the
two
sequences
u
n
and
v
n
defined
on
N
by:
u
0
=
0
;
u
n
+1
=
3
·
u
n
−
2
·
n
+
3
for
all
n
∈
N
v
n
=
3
n
+
n
−
1
1
a
Establish
that
the
two
suites
u
n
and
v
n
have
the
same
first
term.
b
Show
that
the
terms
of
the
sequence
v
n
verify
the
recurrence
relation:
v
n
+1
=
3
·
v
n
−
2
·
n
+
3
2
Justify
the
equality
of
the
two
sequences
u
n
and
v
n
.
E.2385
1
The
sequence
u
n
n
∈
N
is
defined
by
the
following
recur-rence
relation:
u
0
=
2
;
u
n
+1
=
2
·
u
n
−
3
·
n
+
2
for
all
n
∈
N
a
By
studying
the
previous
recurrence
relation,
show
that
u
1
=6
.
b
Determine
the
value
of
the
terms
u
2
and
u
3
.
2
The
terms
of
the
sequence
v
n
n
∈
N
are
defined
by
the
relation:
v
n
=
2
n
+
3
n
+
1
for
all
n
∈
N
a
Give
the
first
4
terms
of
the
sequence
v
n
.
b
For
any
natural
number
n
(
n
∈
N
)
,
establish
the
equal-ity:
2
·
v
n
−
3
·
n
+
2
=
2
n
+1
+
3
·
n
+1
+
1
3
Deduce
the
equality
of
the
sequences
u
n
and
v
n
.
14.
Notions
of
limits:
explicitly
defined
sequences
E.8502
Consider
the
sequence
u
n
whose
terms
are
defined
for
any
natural
number
n
by
the
relation:
u
n
=
10
·
n
−
1
5
·
n
+1
1
a
Using
the
calculator,
complete
the
table
of
values
below
with
values
rounded
to
the
nearest
hundredth
:
n
0
1
2
3
4
5
u
n
b
In
the
reference
frame
below
and
for
n
,
place
the
se-
https://chingmath.fr
chapExoCorrec/2670
sacados/2670
chapExoCorrec/8490
sacados/8490
chapExoCorrec/8489
sacados/8489
chapExoCorrec/2383
sacados/2383
chapExoCorrec/2384
sacados/2384
chapExoCorrec/5136
sacados/5136
chapExoCorrec/2385
sacados/2385
chapExoCorrec/8502
sacados/8502
23456I-12JO
quence
of
points
A
n
whose
coordinates
are
defined
by:
A
n
(
n
;
u
n
)
2
a
Using
the
calculator,
observe
the
representative
curve
C
f
in
an
orthonormal
frame
of
reference
of
the
function
f
defined
by:
f
(
x
)
=
10
·
x
−
1
5
·
x
+
1
b
What
conjecture
can
be
made
about
the
limit
of
the
sequence
u
n
when
n
tends
to
+
∞
?
E.8504
Using
the
calculator,
conjecture
the
limit
of
each
of
the
sequences
defined
below
when
n
tends
to
+
∞
:
the
sequence
u
n
defined
for
any
natural
number
n
(
n
∈
N
)
by:
u
n
=
4
·
n
1+12
·
n
the
sequence
v
n
defined
for
any
natural
number
n
(
n
∈
N
)
by:
v
n
=
n
2
+2
·
n
−
3
the
sequence
w
n
defined
for
any
natural
number
n
(
n
∈
N
)
by:
w
n
=
(
−
1)
n
n
+1
E.8503
1
Let
u
n
be
an
arithmetic
sequence
with
first
term
u
0
and
reason
r
.
Complete
the
double-entry
table
below,
indicating
the
value
of
lim
n
↦→
+
∞
u
n
in
each
case
r>
0
r<
0
u
0
>
0
u
0
<
0
2
Let
v
n
be
a
geometric
sequence
with
first
term
u
0
and
reason
q
.
Complete
the
double-entry
table
below,
indi-cating,
in
each
case
if
possible,
the
value
of
lim
n
↦→
+
∞
v
n
v
0
>
0
v
0
<
0
q>
1
0
<q<
1
−
1
<q<
0
q<
−
1
15.
Notions
of
limits:
sum
of
the
terms
of
a
sequence
E.6029
Consider
the
sequence
u
n
geomet-ric
of
first
term
5
and
reason
2
3
.
Let
S
n
be
the
sum
of
the
(
n
+1)
first
terms
of
the
sequence
u
n
:
S
n
=
u
0
+
u
1
+
·
·
·
+
u
n
−
1
+
u
n
1
Justify
that
the
sequence
S
n
is
increasing.
2
Give
the
expression
of
the
term
S
n
as
a
function
of
n
.
3
a
Using
a
calculator,
complete
the
table
below,
round-ing
values
to
the
nearest
thousandth
:
n
0
1
2
10
20
24
S
n
b
What
conjecture
can
be
made
about
the
limit
of
the
sequence
S
n
when
n
tends
to
+
∞
?
E.6013
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
For
any
natural
number
n
,
let
S
n
be
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:
https://chingmath.fr
23456I-12JO
chapExoCorrec/8504
sacados/8504
chapExoCorrec/8503
sacados/8503
chapExoCorrec/6029
sacados/6029
chapExoCorrec/6013
sacados/6013
ABEtape no0ABEtape no1ABEtape no2ABEtape no3ABEtape no4ABEtape no5
Première ∏gure5cm:::Seconde ∏gure3cm
n
10
100
500
750
1000
u
n
c
What
conjecture
can
be
made
about
the
limit
of
the
terms
of
the
sequence
S
n
when
n
tends
to
+
∞
?
E.6014
The
Heige
Von
Koch
flake
is
con-structed
as
follows
:
We
start
from
a
segment
[
AB
]
of
length
9
cm
.
To
move
from
one
step
to
the
next,
we
cut
each
segment
of
the
figure
into
three
equal
parts
and
replace
the
central
ˇı
segment
with
an
equilateral
triangle.
Here’s
a
representation
of
the
first
6
steps
of
this
construc-tion
:
At
each
n
step,
we
note
u
n
the
length
of
the
ˇ
line
brisée
ı
thus
obtained.
We
thus
construct
a
sequence
of
numbers
u
n
defined
for
any
natural
number
n
.
1
Determine
the
measure
of
the
first
three
terms
of
the
sequence
u
n
.
2
a
In
step
n
,
express
the
number
of
segments
s
n
form-ing
the
ˇ
line
brisée
ı
as
a
function
of
n
.
b
In
step
n
,
express
the
length
‘
n
of
each
of
the
segments
forming
the
ˇ
line
brisée
ı
as
a
function
of
n
.
3
We
note
L
n
the
length
of
the
ˇ
line
brisée
ı
at
step
n
.
This
gives
a
sequence
L
n
of
numerical
terms
defined
for
any
natural
number
n
.
a
Express
the
terms
of
the
sequence
L
n
in
terms
of
their
rank
n
.
b
Complete
the
table
below,
rounding
values
to
the
near-est
hundredth
of
a
centimeter:
n
0
1
10
20
30
L
n
E.6039
In
this
exercise,
any
trace
of
research,
however
incomplete,
or
initiative,
however
unsuccessful,
will
be
taken
into
account
in
the
assessment.
The
quality
of
the
justifications
will
also
be
taken
into
account.
Consider
the
two
figures
below
:
The
first
figure
is
a
square
whose
sides
measure
5
cm
;
The
second
figure
is
composed
of
a
square
whose
sides
measure
3
cm
,
to
complete
the
figure,
we
add
a
new
square
whose
dimensions
have
been
reduced
by
the
co-efficient
4
5
.
We
repeat
this
figure
a
number
of
times,
but
we
don’t
know
how
many
times!
Which
of
these
two
figures
has
the
larger
area?
16.
Further
study:
arithmetic-geometric
sequences
and
variation
E.9844
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
Establish,
for
any
n
∈
N
,
the
equality:
v
n
+1
=
2
·
v
n
b
Give
the
nature
and
characteristic
elements
of
the
straight
line
v
n
.
c
Give
the
direction
of
variation
of
the
sequence
v
on
N
.
Justify
your
answer.
2
a
For
any
n
∈
N
,
set
:
u
n
+1
−
u
n
=
v
n
+1
−
v
n
b
Deduce
the
direction
of
variations
of
the
sequence
u
n
on
N
.
E.9845
Consider
the
sequence
u
n
)
defined
on
N
∗
by:
u
1
=
0
;
u
n
+1
=
0.2
·
u
n
+
0.04
for
any
n
∈
N
∗
1
We
define
the
sequence
v
n
on
N
∗
by
the
relation:
v
n
=
u
n
−
0.05
a
Establish
equality
for
any
n
∈
N
∗
:
v
n
+1
=
0.2
·
v
n
b
Determine
the
nature
and
characteristic
elements
of
the
sequence
v
n
.
2
a
Establish
equality
for
any
n
∈
N
∗
:
u
n
+1
−
u
n
=
v
n
+1
−
v
n
b
Deduce
the
direction
of
variation
of
the
sequence
u
n
E.6668
Consider
the
sequence
u
n
defined
by:
u
0
=
2
;
u
n
+1
=
1
+
2
·
u
n
−
6
for
all
n
∈
N
and
the
sequence
v
n
,
defined
for
any
n
∈
N
,
by:
v
n
=
u
n
−
3
1
Establish
that
the
sequence
v
n
is
a
geometric
sequence
whose
characteristic
elements
and
direction
of
variations
will
be
given.
2
a
For
any
n
∈
N
,
establish
equality:
u
n
+1
−
u
n
=
v
n
+1
−
v
n
b
Determine
the
direction
of
variation
of
the
sequence
u
n
.
https://chingmath.fr
chapExoCorrec/6014
sacados/6014
ABEtape no0ABEtape no1ABEtape no2ABEtape no3ABEtape no4ABEtape no5
chapExoCorrec/6039
sacados/6039
Première ∏gure5cm:::Seconde ∏gure3cm
chapExoCorrec/9844
sacados/9844
chapExoCorrec/9845
sacados/9845
chapExoCorrec/6668
sacados/6668
17.
Further
study:
arithmetic-geometric
sequences
and
explicit
formulas
E.9843
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
+
∞
.
E.9842
We
wish
to
study
the
sequence
(
u
n
)
of
first
term
u
0
=5
defined
by
the
following
recurrence
rela-tion
:
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
a
Show
that
the
sequence
(
v
n
)
is
a
geometric
sequence
whose
first
term
and
reason
will
be
specified.
b
Express
v
n
as
a
function
of
rank
n
.
2
a
Deduce
the
expression
of
u
n
as
a
function
of
n
.
b
For
any
n
∈
N
,
establish
that
:
u
n
+1
−
u
n
=
2
3
·
1
3
n
c
Deduce
the
direction
of
variations
of
the
sequence
u
n
.
E.5368
Consider
the
sequence
u
n
defined
by:
u
0
=
3
;
u
n
+1
=
3
4
·
u
n
+
1
2
for
any
integer
n
∈
N
1
Consider
the
sequence
v
n
defined
by
the
following
re-lation
for
any
natural
number
n
:
v
n
=
1
2
·
u
n
−
1
a
Establish
the
equality
below
for
any
natural
number
n
:
v
n
+1
=
3
4
·
v
n
b
Give
the
direction
of
variation
of
the
sequence
v
n
.
2
Deduce
the
direction
of
variation
of
the
sequence
u
n
.
18.
More:
other
uses
for
auxiliary
suites
E.8487
Consider
the
sequence
v
n
defined
by:
v
0
=
1
;
v
n
+1
=
v
n
+
2
·
n
+
3
for
all
n
∈
N
1
Determine
the
first
five
terms
of
the
sequence
v
n
.
2
What
conjecture
can
be
made
about
the
terms
of
the
sequence
v
n
?
We
define
the
sequence
w
n
defined
by:
w
n
=
v
n
+1
−
v
n
for
any
n
∈
N
1
Justify
that
the
sequence
w
n
is
an
arithmetic
sequence.
Specify
the
characteristic
elements
of
this
sequence.
2
Determine
the
expression
of
the
sum
S
of
the
first
n
terms
of
the
sequence
w
n
.
3
Noting
the
equality
n
−
1
k
=0
w
k
+
v
0
=
v
n
,
deduce
the
expres-sion
of
the
term
v
n
as
a
function
of
n
.
4
Confirm
the
conjecture
made
in
question
b
.
19.
Further
development:
jointly
defined
suites
E.8498
Consider
the
two
sequences
u
n
and
v
n
defined
for
any
natural
number
n
by
the
relations
:
u
0
=
3
v
0
=
1
;
u
n
+1
=
2
·
u
n
+
v
n
2
v
n
+1
=
u
n
+
3
·
v
n
3
1
Determine
the
first
three
terms
of
the
sequences
u
n
and
v
n
.
2
Admit
that
the
terms
of
the
sequences
u
n
and
v
n
are
strictly
positive
numbers.
Show
that
the
sequences
u
n
and
v
n
are
increasing
on
N
.
E.4235
Consider
the
sequences
u
n
and
v
n
defined
by:
u
0
=
0
;
u
n
+1
=
u
n
+
v
n
2
for
all
n
∈
N
v
0
=
12
;
v
n
+1
=
u
n
+
2
·
v
n
3
for
any
n
∈
N
1
Demonstrate
that
the
sequence
w
n
defined
by
w
n
=
v
n
−
u
n
is
a
convergent
geometric
sequence
and
that
all
its
terms
are
positive.
2
Show
that
the
sequence
u
n
is
increasing
and
then
that
the
sequence
v
n
is
decreasing.
https://chingmath.fr
chapExoCorrec/9843
sacados/9843
chapExoCorrec/9842
sacados/9842
chapExoCorrec/5368
sacados/5368
chapExoCorrec/8487
sacados/8487
chapExoCorrec/8498
sacados/8498
chapExoCorrec/4235
sacados/4235
Motif0Motif1Motif2Motif3
Motif0Motif1Motif2Motif3
20.
Unclassified
financial
years
E.5973
1
a
Consider
the
sequence
u
n
defined
by
the
relation:
u
0
=
0
;
u
n
+1
=
1
2
−
u
n
for
all
n
∈
N
Determine
the
first
four
terms
of
the
sequence
u
n
.
b
Consider
the
sequence
v
n
defined
by
the
relation:
v
n
=
n
n
+
1
for
any
n
∈
N
.
Determine
the
first
four
terms
of
the
sequence
v
n
.
c
What
conjecture
can
be
made
about
the
sequences
u
n
and
v
n
?
2
a
Simplify
the
following
expression
:
v
n
+1
·
2
−
v
n
b
Justify
that
the
two
suites
u
n
and
v
n
are
equal.
E.10569
Consider
the
step-by-step
pattern
con-struction
whose
first
five
steps
are
shown
below
:
1
How
many
tiles
are
needed
to
construct
pattern
4?
pat-tern
5?
2
We
note
u
n
the
number
of
tiles
required
to
construct
pattern
n
.
a
Give
the
recurrence
formula
verified
by
the
sequence
u
n
.
b
Establish
that
the
terms
of
the
sequence
u
n
admit
the
explicit
formula
:
u
n
=
2
n
2
+
5
n
+
4
E.10570
Consider
the
step-by-step
pattern
con-struction
whose
first
five
steps
are
shown
below
:
1
How
many
tiles
are
needed
to
construct
pattern
4?
pat-tern
5?
2
We
note
u
n
the
number
of
tiles
needed
to
construct
pat-tern
n
.
a
Give
the
recurrence
formula
verified
by
the
sequence
u
n
.
b
Establish
that
the
terms
of
the
sequence
u
n
verify
the
explicit
formula
:
u
n
=
1
3
·
n
3
+
3
2
·
n
2
+
13
6
·
n
+
1
https://chingmath.fr
chapExoCorrec/5973
sacados/5973
sacados/10569
Motif0Motif1Motif2Motif3
sacados/10570
Motif0Motif1Motif2Motif3