image PNG : /home/_math/_exercice/d0/471/metapost/exo_faux.png
-122-∞∞-122-∞∞-122-∞∞2x1x−2(2xx−
-∞∞-∞∞-∞∞3x−43−xg(x
3.
Construction
of
sign
tables
E.468
1
Consider
the
function
f
defined
by
the
relation:
f
(
x
)
=
2
x
2
−
3
x
−
2
In
this
question,
we
will
study
the
sign
of
the
function
f
.
a
Establish
equality:
f
(
x
)=(2
x
+1)(
x
−
2)
.
b
Solve
the
following
two
inequations
:
2
x
+
1
<
0
;
x
−
2
<
0
c
In
the
table
below
and
for
the
two
factors
2
x
+1
and
x
−
2
,
color:
in
blue
the
intervals
over
which
the
factor
is
positive
;
in
red
the
intervals
over
which
the
factor
is
negative.
d
Complete
the
third
line
using
the
sign
rule
for
a
prod-uct.
e
Solve
the
inequation
:
f
(
x
)
0
.
2
Consider
the
function
g
whose
image
of
a
number
x
is
given
by
the
relation:
g
(
x
)
=
−
3
x
2
+
13
x
−
12
a
Establish
the
following
equality:
g
(
x
)=(3
x
−
4)(3
−
x
)
b
As
in
the
previous
question,
complete
the
table
below
:
c
Deduce
the
set
of
solutions
to
the
inequation
g
(
x
)
<
0
E.469
1
a
Solve
at
R
the
following
inequations
:
4
−
2
x
0
;
5
x
+
15
0
b
Deduce
the
solutions
of
the
inequations
:
4
−
2
x
<
0
;
5
x
+
15
<
0
2
a
In
the
first
two
lines
of
the
sign
table,
indicate
the
sign
of
the
expressions
on
R
:
x
−∞
+
∞
4
−
2
x
5
x
+15
(4
−
2
x
)(5
x
+15)
b
Complete
the
third
row
of
the
table
to
indicate
the
sign
of
the
product
(4
−
2
x
)(5
x
+15)
on
R
.
c
Deduce
the
set
of
solutions
to
the
inequation
:
(4
−
2
x
)(5
x
+
15)
0
E.4380
Consider
the
functions
f
and
g
whose
images
of
the
number
x
are
respectively
defined
by:
f
(
x
)
=
2
−
x
×
x
−
5
;
g
(
x
)
=
(2
−
x
)(
x
−
5)
1
a
Justify
that
the
function
f
is
not
defined
for
the
number
3
.
b
Determine
the
definition
set
of
the
function
f
.
2
a
Determine
the
image
of
the
number
3
by
the
func-tion
g
.
b
Determine
the
definition
set
of
the
function
g
.
4.
Product
Specifications
Table
E.4455
Complete
the
sign
tables
below
:
1
x
−∞
+
∞
2
x
+
1
3
+
x
(2
x
+1)(3+
x
)
2
x
−∞
+
∞
2
−
x
4
x
−
3
(2
−
x
)(4
x
−
3)
E.4876
Complete
the
sign
tables
below
:
1
x
−∞
+
∞
1
−
x
2
x
+
1
(1
−
x
)(2
x
+1)
2
x
−∞
+
∞
x
−
3
−
2
x
+
4
(
x
−
3)(
−
2
x
+4)
https://chingmath.fr
chapExoCorrec/468
sacados/468
-122-∞∞-122-∞∞-122-∞∞2x1x−2(2xx−
-∞∞-∞∞-∞∞3x−43−xg(x
chapExoCorrec/469
sacados/469
chapExoCorrec/4380
sacados/4380
chapExoCorrec/4455
sacados/4455
chapExoCorrec/4876
sacados/4876
E.460
Establish
the
sign
table
for
algebraic
expressions
:
a
(
x
+
1)(2
−
x
)
b
−
(2
x
+
4)(
x
−
2)
c
(
x
+
1)
2
E.11648
Construire
le
tableau
de
signes
de
cha-cune
des
expressions
ci-dessous
:
a
(2
x
−
15)(2
x
−
3)
b
x
(
x
+
1)
E.11650
Construire
le
tableau
de
signe
des
ex-pressions
:
a
(
−
2
x
−
1)(
x
+
1)
b
(
−
x
+
2)(
x
+
3)
5.
Table
of
Signs
for
a
Quotient
E.9787
Complete
the
sign
tables
below
:
1
x
−∞
+
∞
x
+
5
−
2
x
−
8
x
+
5
−
2
x
−
8
2
x
−∞
+
∞
x
−
1
4
−
x
−
x
−
1
(
x
−
1)(4
−
x
)
−
x
−
1
E.9788
Complete
the
sign
tables
below
:
1
x
−∞
+
∞
2
+
x
2
−
x
2
+
x
2
−
x
2
x
−∞
+
∞
4
x
+
1
x
−
1
x
(4
x
+1)(
x
−
1)
x
E.11712
Construire
le
tableau
de
signe
des
ex-pressions
:
a
5
x
−
3
4
x
+
7
b
−
2
x
+
5
6
x
+
15
6.
Inequations
and
sign
tables
E.480
Solve
the
following
inequalities:
a
(
x
+
4)(1
−
2
x
)
0
b
3
+
x
2
−
x
0
E.9819
Solve
the
following
inequalities:
a
(3
−
2
x
)(5
x
+
2)
0
b
(3
x
+
1)(4
−
2
x
)
0
E.9790
Solve
the
inequation
:
−
(
x
+
1)(
x
−
2)
1
−
x
>
0
E.9820
Solve
inequalities:
a
(5
−
2
x
)(
x
−
1)
3
x
−
2
>
0
b
−
(2
x
+
1)
2
(4
x
−
3)(1
−
2
x
)
0
E.465
1
Expand
:
(2
x
+
1)(
x
−
1)
2
Solve
the
following
inequation
:
2
x
2
−
x
−
1
x
2
+
1
0
.
E.442
1
Expand
:
(
x
−
1)(
x
−
5)
2
Solve
:
(
x
−
3)
2
−
4
3
−
2
x
<
0
Hint:
we
will
use
the
result
of
question
1
E.445
Consider
the
function
f
defined
by
the
following
relationship
:
f
:
x
↦−→
x
+
1
−
2
x
2
+
7
x
−
3
1
Establish
the
following
equality:
−
2
x
2
+
7
x
−
3
=
(2
x
−
1)(3
−
x
)
2
Give
the
definition
set
of
the
function
f
.
3
a
Draw
up
the
sign
table
for
the
function
f
on
its
def-inition
set.
b
Solve
the
inequation
:
f
(
x
)
0
E.11713
Résoudre
les
inéquations
suivantes
:
a
(
x
+
4)(5
−
2
x
)
0
b
(3
−
x
)(3
−
6
x
)
<
0
E.11714
Résoudre
les
inéquations
suivantes
:
a
5
x
+
2
x
−
3
0
b
5
−
2
x
x
+
4
0
https://chingmath.fr
chapExoCorrec/460
sacados/460
chapExoCorrec/11648
sacados/11648
chapExoCorrec/11650
sacados/11650
chapExoCorrec/9787
sacados/9787
chapExoCorrec/9788
sacados/9788
chapExoCorrec/11712
sacados/11712
chapExoCorrec/480
sacados/480
chapExoCorrec/9819
sacados/9819
chapExoCorrec/9790
sacados/9790
chapExoCorrec/9820
sacados/9820
chapExoCorrec/465
sacados/465
chapExoCorrec/442
sacados/442
chapExoCorrec/445
sacados/445
chapExoCorrec/11713
sacados/11713
chapExoCorrec/11714
sacados/11714
-2-1234I-12JOCf
-6-5-4-3-2-12345678I-123JOCg
x-6-5-4-3-2-10123y-2-1123Cf
-3-2-10123-4-224Cf
7.
Graphical
solutions
to
inequalities
and
sign
chart
E.5027
Consider
the
function
f
defined
on
the
interval
−
2
;
4
,
whose
representative
curve
C
f
is
given
in
the
orthonormal
coordinate
system
O
;
I
;
J
below
:
1
We
will
leave
the
construction
lines
necessary
for
solving
the
following
questions
:
a
Graphically
determine
the
image
of
the
number
2
by
the
function
f
.
b
Graphically
determine
the
antecedents
of
the
number
1
by
the
function
f
.
2
a
Graphically
determine
the
set
of
solutions
to
the
in-equality
f
(
x
)
0
b
Complete
the
sign
table
for
the
function
f
:
x
f
(
x
)
E.365
In
an
orthonormal
coordinate
system
(
O
;
I
;
J
)
,
consider
the
curve
C
g
representing
the
function
g
:
1
Give,
without
justification,
the
domain
of
the
function
g
.
2
a
Graphically,
solve
the
equation
f
(
x
)=0
.
b
Complete
the
sign
table
for
the
function
f
.
x
f
(
x
)
E.9656
Consider
a
function
f
whose
rep-resentative
curve
C
f
is
given
in
the
orthonormal
coordinate
system
below
:
1
Give
the
domain
of
the
function
f
.
2
a
Graphically,
give
the
solutions
to
the
equation
f
(
x
)=0
.
b
Draw
up
the
sign
table
for
the
function
f
.
8.
Graphical
readings
and
algebraic
manipulations
E.458
Consider
the
function
f
defined
on
R
by
the
relation:
f
(
x
)
=
x
3
−
3
x
+
2
1
Graphically,
determine
the
set
of
solutions
to
the
inequa-tion
f
(
x
)
>
0
.
https://chingmath.fr
chapExoCorrec/5027
sacados/5027
-2-1234I-12JOCf
chapExoCorrec/365
sacados/365
-6-5-4-3-2-12345678I-123JOCg
chapExoCorrec/9656
sacados/9656
x-6-5-4-3-2-10123y-2-1123Cf
chapExoCorrec/458
sacados/458
-3-2-10123-4-224Cf
-2-10123-4-224Cf
-7-6-5-4-3-2-1234567I-4-3-2-1234JOCfCg
-2-1234I-224JO
2
a
Establish
the
following
equality:
f
(
x
)=(
x
+2)(
x
−
1)
2
b
Draw
up
the
sign
table
for
the
function
f
at
R
.
c
Deduce
the
set
of
solutions
to
the
inequation
:
f
(
x
)
>
0
E.446
Consider
the
function
f
whose
image
of
a
number
x
is
defined
by
the
expression
:
f
(
x
)
=
−
x
3
+
2
x
2
+
x
−
2
In
the
plane
provided
with
an
orthogonal
reference
frame,
we
have
drawn
the
curve
C
f
representative
of
the
function
f
:
1
By
graphical
reading,
give
the
intervals
over
which
the
function
f
is
strictly
positive.
2
Show
the
equality:
−
x
3
+2
x
2
+
x
−
2=
−
(
x
−
2)(
x
2
−
1)
3
a
Draw
up
the
table
of
signs
for
f
.
b
Deduce
the
solutions
of
the
inequation
:
f
(
x
)
>
0
.
9.
Relative
positions
of
curves:
graphic
resolution
E.462
In
the
plane
provided
with
a
refer-ence
frame
O
;
I
;
J
,
consider
the
two
curves
C
f
and
C
g
rep-resentative
respectively
of
the
functions
f
and
g
defined
on
−
7
;
7
:
1
Determine,
graphically,
the
coordinates
of
the
intersec-tion
points
of
the
curves
C
f
and
C
g
.
2
Graphically,
solve
the
inequation
:
g
(
x
)
f
(
x
)
E.372
Consider
the
function
f
whose
rep-resentation
is
given
below
in
the
orthogonal
reference
frame
O
;
I
;
J
)
:
We
are
interested
in
the
affine
function
g
defined
by
the
rela-tion
:
g
:
x
↦−→
x
+
1
1
Draw
the
representative
curve
of
the
function
g
in
the
above
reference
frame.
2
Graphically,
solve
the
equation
:
f
(
x
)=
g
(
x
)
.
3
Graphically
solve
the
inequation
:
f
(
x
)
g
(
x
)
https://chingmath.fr
chapExoCorrec/446
sacados/446
-2-10123-4-224Cf
chapExoCorrec/462
sacados/462
-7-6-5-4-3-2-1234567I-4-3-2-1234JOCfCg
chapExoCorrec/372
sacados/372
-2-1234I-224JO
-4-3-2-1234I-3-2-1234JOCfCg
-2-1234I-6-5-4-3-2-123JOCfCg
1xyx141
E.2142
In
the
plane
provided
with
an
or-thonormal
reference
frame,
we
give
the
representative
curves
of
the
functions
f
and
g
defined
on
the
interval
[
−
4
;
4]
:
Consider
the
inequation
:
f
(
x
)
<g
(
x
)
1
Which
of
the
numbers
below
are
solutions
of
this
inequa-tion
:
a
−
2.5
b
−
0.25
c
1
2
Solve
this
inequation
graphically.
10.
Relative
positions
of
curves:
algebraic
solution
E.4915
1
In
the
plane
provided
with
a
reference
frame
O
;
I
;
J
orthogonal,
consider
the
representative
curves
C
f
and
C
g
representative
of
the
functions
f
and
g
.
Solve
grahpically
on
the
interval
−
2
;
4
the
following
inequation
:
f
(
x
)
<g
(
x
)
2
The
functions
f
and
g
are
defined
on
R
by
the
expres-sions
:
f
(
x
)
=
x
3
−
3
x
2
−
x
+
1
;
g
(
x
)
=
−
x
2
+
2
x
+
1
a
Determine
the
expression
of
the
polynomial
P
of
degree
1
verifying
the
equality:
x
3
−
2
x
2
−
3
x
=(
x
2
−
3
x
)
×
P
b
Deduce
on
which
intervals
the
curve
C
g
is
strictly
above
C
f
.
E.8192
In
the
plane
provided
with
a
refer-ence
frame
O
;
I
;
J
orthogonal,
consider
the
representative
curves
C
f
and
C
g
representative
of
the
functions
f
and
g
where
the
functions
f
and
g
are
defined
by:
f
(
x
)
=
6
x
3
+
2
x
2
+
x
+
1
;
g
(
x
)
=
2
x
2
+
19
x
+
13
1
Determine
the
reals
a
and
b
realizing
the
identity:
6
x
3
−
18
x
−
12=(2
x
+2)(3
x
+3)(
ax
+
b
)
2
Deduce
on
which
intervals
the
curve
C
g
is
strictly
above
C
f
.
11.
Problems
E.2868
A
manufacturer
of
cardboard
boxes
uses
rolls
to
produce
a
41
cm
wide
strip
of
cardboard
from
which
he
traces
and
cuts
out
box
patterns
before
gluing
them
on.
He
arranges
his
patterns
as
shown
in
the
drawing
below
:
https://chingmath.fr
chapExoCorrec/2142
sacados/2142
-4-3-2-1234I-3-2-1234JOCfCg
chapExoCorrec/4915
sacados/4915
-2-1234I-6-5-4-3-2-123JOCfCg
chapExoCorrec/8192
sacados/8192
chapExoCorrec/2868
sacados/2868
1xyx141
x9cm4cmABCDEF
5m10mxABCDEFG
The
boxes,
in
the
shape
of
straight
blocks,
have
two
x
cm
-square
faces,
fitted
with
two
1
cm
-wide
tabs
for
gluing,
and
four
other
faces
whose
dimensions
in
cm
are
x
and
y
,
as
well
as
a
flap
for
closure.
1
a
Give
an
expression
for
y
as
a
function
of
x
.
b
Justify
that
the
value
of
x
belongs
to
the
interval
0
;
19.5
.
2
Demonstrate
that
the
volume
V
,
in
cm
3
,
of
the
box
is
given,
as
a
function
of
x
,
by
the
formula
:
V
=
39
x
2
−
2
x
3
3
a
Determine
the
expression
of
the
polynomial
P
veri-fying
the
equality:
39
x
2
−
2
x
3
−
972
=
(
x
−
18)(
x
−
6)
×
P
b
Deduce
the
values
of
x
for
which
the
volume
V
is
greater
than
972
cm
3
.
4
a
Determine
the
expression
of
the
polynomial
Q
veri-fying
the
equality:
V
(
x
)
−
2197=(
−
2
x
−
13)
×
Q
b
Deduce
the
sign
table
for
the
expression
:
V
(
x
)
−
2197
.
c
Give
the
maximum
volume
the
manufacturer
can
ob-tain
with
this
type
of
box;
for
what
value
of
x
is
this
maximum
reached?
E.1979
Consider
the
triangle
ABC
right-angled
A
such
that
:
AB
=
9
cm
;
AC
=
4
cm
Consider
a
point
D
belonging
to
segment
[
AB
]
and
note
x
the
length
of
segment
[
BD
]
.
From
the
point
D
we
construct
a
rectangle
DEFA
such
that
:
E
∈
[
BC
]
;
F
∈
[
AC
]
Note
A
the
area
of
the
rectangle
DEFA
.
1
a
Determine
the
expression
for
length
FA
as
a
func-tion
of
x
.
b
Justify,
briefly,
that
the
real
number
x
belongs
to
the
interval
0
;
9
.
2
Establish
that
the
area
A
is
expressed
as
a
function
of
x
by:
A
(
x
)
=
4
x
−
4
9
·
x
2
3
a
Draw
up
the
table
of
variations
of
the
function
A
on
the
interval
0
;
9
.
b
What
is
the
maximum
area
reached
by
the
A
area?
4
We
wish
to
know
the
values
of
x
for
which
the
area
A
has
greater
than
or
equal
to
5
cm
2
:
a
Establish
the
following
factorization
:
−
4
x
2
+
36
x
−
45
=
(2
x
−
15)(3
−
2
x
)
b
Solve
the
inequation
:
A
(
x
)
5
.
E.11721
1
a
Etablir
la
factorisation
:
−
3
x
2
+10
x
−
3=(
x
−
3)(1
−
3
x
)
b
Résoudre
l’inéquation:
−
3
x
2
+
10
x
−
3
>
0
2
On
considère
la
figure
ci-dessous
composée
des
deux
rect-angles
ABCD
et
AEFG
:
Déterminer
pour
quelle
valeur
de
x
,
l’aire
de
la
partie
hachurée
est
strictement
supérieure
à
53
m
2
.
https://chingmath.fr
chapExoCorrec/1979
sacados/1979
x9cm4cmABCDEF
chapExoCorrec/11721
sacados/11721
5m10mxABCDEFG
3m9mxABCDEFG
ABCDEFGHI2xx4cm4cm
11x211x·(1x2·(1x122x−12x−12x
E.11722
1
a
Etablir
la
factorisation
:
−
2
x
2
+9
x
−
10=(
x
−
2)(5
−
2
x
)
b
Résoudre
l’inéquation:
−
2
x
2
+
9
x
−
10
0
2
On
considère
la
figure
ci-dessous
composée
des
deux
rect-angles
ABCD
et
AEFG
:
Déterminer
pour
quelle
valeur
de
x
,
l’aire
de
la
partie
hachurée
est
strictement
supérieure
à
37
m
2
.
E.11723
1
a
Etablir
la
factorisation
:
4
x
2
−
12
x
+
27
4
=
4
x
−
9
x
−
3
4
b
Résoudre
l’inéquation:
4
x
2
−
12
x
+
27
4
0
2
On
considère
la
figure
ci-dessous
composée
:
du
carré
AEFG
,
de
deux
rectangles
ABCD
et
CIFH
.
Les
points
B
,
D
,
I
,
H
ap-partiennent
aux
côtés
du
carré
AEFG
.
On
considère
le
domaine
grisé
représenté
ci-contre
et
on
note
son
aire
A
:
(les
mesures
sont
exprimées
en
centimètre)
Déterminer
l’ensemble
des
valeurs
de
x
réalisant
l’inéquation:
A
37
4
Indication
:
toute
trace
de
recherche
ou
de
prise
d’initiative
sera
prise
en
compte
dans
l’évaluation.
12.
Deepening:
reflection
on
algebraic
operations
E.471
Here’s
a
student’s
solution
to
an
in-equation
:
1
is
−
2
the
solution
to
the
inequation
:
1
1+
x
2
?
ab
What
can
we
deduce
from
the
proposed
resolution?
2
We
break
down
the
student’s
resolution,
indicating
the
algebraic
manipulation
performed
at
each
step
by
the
student.
Complete
the
diagram
below
:
3
a
What
can
be
the
sign
of
the
expression
1+
x
?
b
Deduce
the
error
made
by
the
student.
4
Solve
the
inequation
:
1
1+
x
2
E.479
A
student
has
produced
the
following
solution
to
an
inequation
:
1
is
the
number
−
1
solution
of
the
inequation
:
x
2
+
4
x
4
ab
What
can
we
deduce
about
the
student’s
proposed
resolution?
2
Solve
this
inequation
correctly.
https://chingmath.fr
chapExoCorrec/11722
sacados/11722
3m9mxABCDEFG
chapExoCorrec/11723
sacados/11723
ABCDEFGHI2xx4cm4cm
chapExoCorrec/471
sacados/471
11x211x·(1x2·(1x122x−12x−12x
chapExoCorrec/479
sacados/479
13.
Further
study:
systems
of
inequalities
E.319
Give
the
value
of
a
so
that
the
system
below
has
as
its
solution
the
interval
1
;
3
:
3
x
+
2
5
1
2
−
x
a
E.318
Three
real
numbers
a
,
b
and
c
verify
the
following
system
:
a
·
b
·
c
<
0
a
·
b
>
0
a
+
b
>
0
Find
the
sign
of
these
three
numbers.
E.348
Solve
the
following
systems
of
equa-tions
:
1
2
x
−
3
<
5
x
−
1
x
+
4
3
x
−
2
2
3
x
−
3
>
x
+
1
2
x
+
1
2
x
+
1
14.
Deepening:
manipulation
of
frames
E.317
Consider
a
ABCD
square
with
5
cm
sides.
1
Give
the
exact
length
of
the
diagonals
of
this
square.
2
Knowing
that
:
1.41
<
2
<
1.42
Give
a
frame
for
the
length
of
this
diagonal.
E.315
1
Let
a
∈
R
such
that
1
2
<a<
1
,
specify
which
frames
are
verified
by
a
:
a
1
2
<
1
a
<
2
b
0
<a
<
2
a
c
1
4
<a
2
<
4
2
By
case
disjunction
for
a
∈
−
1
;
0
and
a
∈
0
;
2
,
give
a
frame
for
a
2
and
a
3
for
−
1
<a<
2
.
15.
Unclassified
exercises
E.470
When
solving
an
equation
or
inequal-ity,
the
ˇ
domain
of
solution
ı
ı
is
the
set
of
values
that
the
unknown
x
can
take.
We
will
then
look
for
solutions
among
the
values
in
the
solution
set.
1
Here
is
a
student’s
solution
to
equation
x
2
=3
x
:
(
E
)
:
x
2
=
3
x
x
2
x
=
3
x
x
x
=
3
From
this,
the
student
concludes
that
the
equation
has
one
solution
:
3
.
a
This
equation
has
a
second
solution.
Which
one?
b
In
their
solution
method,
this
student
used
R
∗
as
the
solution
set
rather
than
R
.
Explain
why?
2
A
student
solves
an
inequality
as
follows
:
(
I
)
:
x
+
1
x
2
x
+
1
2
x
1
x
The
student
concludes
that
the
set
of
solutions
is
the
interval
[1
;
+
∞
[
a
Give
the
domain
of
the
algebraic
expression
x
+1
x
.
b
Show
that
−
1
is
a
solution
to
the
inequality.
c
What
mistake
did
the
student
make?
Implicitly,
what
solution
set
did
he
or
she
use?
d
Solve
the
inequality
(
I
)
using
a
sign
table.
Additional
question:
3
Without
using
sign
tables
:
a
Assume
that
x
is
a
strictly
negative
number;
solve
the
inequality
(
I
)
.
b
Assume
that
x
is
a
strictly
positive
number;
solve
the
inequality
(
I
)
.
c
Use
this
to
deduce
and
find
the
answer
to
question
3
.
https://chingmath.fr
chapExoCorrec/319
sacados/319
chapExoCorrec/318
sacados/318
chapExoCorrec/348
sacados/348
chapExoCorrec/317
sacados/317
chapExoCorrec/315
sacados/315
chapExoCorrec/470
sacados/470
0;600;800;400;20Image A0;360;640;160;04Image B0;770;890;630;45Image C
00.510.51Cf
E.309
The
shortest
distance
between
two
points
is
a
straight
line.
This
fact
is
expressed
by
the
triangle
inequality
relating
the
distances
between
three
points
:
for
any
points
A
,
B
,
C
in
the
plane,
the
following
always
holds
:
AB
AC
+
CB
(Passing
through
point
C
lengthens
the
path
unless
it
lies
on
segment
)
.
We
will
construct
an
isosceles
triangle
DEF
at
F
such
that
DE
=5
.
Let
x
=
EF
=
DF
1
Be
given.
Can
this
triangle
be
constructed
for
x
=2
?
2
Give
a
range
of
possible
values
for
x
.
3
Express
the
value
p
of
the
perimeter
of
triangle
DEF
in
terms
of
the
value
x
.
4
For
x
satisfying
the
range
:
2
;
5
x
5
.
Give
the
corresponding
bounding
rectangle
for
p
.
E.6755
A
black-and-white
digital
image
is
made
up
of
small
squares
(pixels)
ranging
in
color
from
white
through
all
shades
of
gray
to
black.
Each
shade
is
coded
by
a
real
x
as
follows
:
x
=0
for
white
;
x
=1
for
black;
x
=0.01
;
x
=0.02
and
so
on
up
to
x
=0.99
in
steps
of
0.01
for
all
intermediate
shades
(from
light
to
dark)
.
The
image
A
,
below,
is
composed
of
four
pixels
and
gives
a
sample
of
these
shades
with
their
codes.
Image
retouching
software
uses
digital
functions
known
as
ˇ
re-touching
functions
ı.
A
function
f
defined
on
the
interval
0
;
1
is
said
to
ˇ
function
of
retouche
ı
if
it
has
the
following
four
properties
:
f
(0)=0
;
f
(1)=1
;
f
is
continuous
on
the
interval
0
;
1
;
f
is
increasing
on
the
interval
0
;
1
.
A
shade
coded
x
is
said
to
be
darkened
by
the
function
f
if
f
(
x
)
>x
,
and
lightened,
if
f
(
x
)
<x
.
if
f
(
x
)=
x
2
,
a
pixel
of
coded
shade
0.2
will
take
on
the
coded
shade
0.2
2
=0.04
.
Image
A
will
be
transformed
into
image
B
below.
If
f
(
x
)=
x
,
the
coded
shade
0.2
will
take
on
the
coded
shade
0.2
≈
0.45
.
The
image
A
will
be
transformed
into
the
image
C
below.
Consider
the
function
f
defined
on
the
interval
0
;
1
by:
f
(
x
)
=
4
x
3
−
6
x
2
+
3
x
We
admit
that
the
function
f
is
a
touch-up
function.
Its
representative
curve
C
f
is
given
below
:
1
Graphically
solve
the
inequation
f
(
x
)
x
,
using
the
graph
given
below,
showing
the
useful
dotted
lines.
2
Interpret
this
result
in
terms
of
lightening
or
darkening.
https://chingmath.fr
chapExoCorrec/309
sacados/309
chapExoCorrec/6755
sacados/6755
0;600;800;400;20Image A0;360;640;160;04Image B0;770;890;630;45Image C
00.510.51Cf
012345678910111213141524681012141618202224262830323436384042444648505254C
nombre de pièces en milliers024681012141618202224262830milliers d’euros50100150200250300350400450500CR
E.7005
The
company
BBE
(Bio
Bois
Én-ergie)
manufactures
and
sells
wood
pellets
to
fuel
boilers
and
stoves
in
homes
and
communities.
The
company
produces
between
1
and
15
tons
of
pellets
per
day.
Daily
manufacturing
costs
are
modeled
by
the
function
C
defined
on
the
interval
1
;
15
by:
C
(
x
)
=
0.3
·
x
2
−
x
+
e
−
x
+5
où
x
denotes
the
quantity
of
pellets
in
tons
and
C
(
x
)
the
corresponding
daily
manufacturing
cost
in
hundreds
of
euros.
In
the
company
BBE
the
selling
price
of
one
ton
of
wood
pellets
is
300
euros.
The
company’s
daily
revenue
is
therefore
given
by
the
function
R
defined
on
the
interval
1
;
15
by:
R
(
x
)
=
3
·
x
où
x
denotes
the
quantity
of
pellets
in
tons
and
R
(
x
)
the
corresponding
daily
revenue
in
hundreds
of
euros.
We
define
by
D
(
x
)
the
company’s
daily
net
income
in
hundreds
of
euros,
i.e.
the
difference
between
revenue
R
(
x
)
and
cost
C
(
x
)
,
où
x
denotes
the
quantity
of
pellets
in
tons.
On
the
graph
below,
we
give
C
and
Δ
the
respective
graph-ical
representations
of
the
functions
C
and
R
in
a
frame
of
reference
with
origin
O
.
The
following
questions
will
be
answered
using
the
graph,
and
with
the
precision
permitted
by
it.
No
justification
is
required.
1
Determine
the
quantity
of
pellets
in
tons
for
which
the
company’s
daily
cost
is
minimal.
2
a
Determine
the
values
C
(6)
and
R
(6)
then
derive
an
estimate
of
of
the
daily
net
income
in
euros
generated
by
the
company
for
6
tons
of
pellets
manufactured
and
sold.
b
Determine
the
possible
quantities
of
pellets
in
tons
that
the
company
must
produce
and
sell
daily
to
generate
a
positive
net
result,
i.e.
a
profit.
E.7055
A
company
produces
and
sells
electronic
components.
Its
monthly
production
capacity
is
between
1
000
and
30
000
pieces.
It
is
assumed
that
all
production
is
marketed.
Given
below
are
R
and
C
the
respective
graphical
representa-tions
of
the
revenue
and
cost
functions
on
the
interval
1
;
30
.
By
graphical
reading,
give
an
estimate
of
the
values
requested.
1
What
is
the
production
cost
of
21
000
pieces?
2
For
what
quantities
of
parts
produced,
does
the
company
make
a
profit?
3
For
what
number
of
pieces
produced
is
the
profit
maxi-mum?
https://chingmath.fr
chapExoCorrec/7005
sacados/7005
012345678910111213141524681012141618202224262830323436384042444648505254C
chapExoCorrec/7055
sacados/7055
nombre de pièces en milliers024681012141618202224262830milliers d’euros50100150200250300350400450500CR
nombre de jours01020304050607080milliers d’habitants24681012
E.7060
The
population
evolution
of
a
sea-side
resort
for
the
summer
2015
was
modeled
by
a
function
f
,
defined
on
the
interval
0
;
70
,
whose
representative
curve
is
given
below.
Where
x
is
the
number
of
days
after
1
er
July,
f
(
x
)
denotes
the
population
in
thousands.
Thus,
x
=30
corresponds
to
31
July
and
f
(30)
represents
the
population
expected
to
be
accommodated
on
31
July.
It
is
estimated
that
one
inhabitant
will
use
between
45
and
55
liters
of
water
per
day.
The
answers
to
the
following
questions
are
to
be
provided
by
graphical
reading.
1
a
Estimate
the
maximum
number
of
inhabitants
present
in
the
seaside
resort
according
to
this
model
during
the
summer
2015
and
specify
when
this
maxi-mum
would
be
reached.
b
The
commune
is
able
to
supply
600
000
liters
of
water
per
day,
is
this
enough?
2
Estimate
the
number
of
days
on
which
the
number
of
in-habitants
of
the
resort
is
expected
to
remain
above
80
%
of
the
maximum
number
expected.
E.5661
Complete
the
table
below
:
a
b
Compare
a
and
b
Sign
of
b
−
a
5
3
2.7
4
3
7
5
7
4
3
5
6
4
ı
E.6429
1
Give
the
sign
of
each
of
the
following
calculations
:
a
5
−
3
b
2.4
−
(
−
3.2)
c
3.6
−
7.9
d
2
3
−
5
6
e
6
14
−
9
21
f
3
−
ı
2
Deduce
from
the
previous
question
the
comparison
of
the
following
numbers
:
a
5
:
:
:
3
b
2.4
:
:
:
−
3.2
c
3.6
:
:
:
7.9
d
2
3
:
:
:
5
6
e
6
14
:
:
:
9
21
f
3
:
:
:
ı
https://chingmath.fr
chapExoCorrec/7060
sacados/7060
Extrait Antilles-Guyane
Septembre 2015
nombre de jours01020304050607080milliers d’habitants24681012
chapExoCorrec/5661
sacados/5661
chapExoCorrec/6429
sacados/6429