- Plan configuration (4 exercices)
- Plane transformations (8 exercices)
- Annals on plane configurations (4 exercices)
- Annals on plane transformations (2 exercices)
- Autes annales (1 exercice)
E.3820
The
complex
plane
is
referred
to
a
O
;
−→
u
;
−→
v
orthonormal
reference
frame.
1
Determine
the
exponential
form
of
the
complex
number:
2
4
·
−
1
+
i
2
Consider
the
transformation
f
of
the
plane
which,
to
any
point
M
of
affix
z
,
associates
the
point
M
of
affix
z
such
that
:
z
=
2
4
·
−
1
+
i
·
z
Determine
the
nature
and
characteristic
elements
of
the
transformation
f
.
E.3821
The
complex
plane
is
referenced
to
O
;
−→
u
;
−→
v
orthonormal
direct.
Consider
the
point
I
of
affix
i
and
the
point
A
of
affix
:
z
=
3
+
2
·
i
1
Show
that
the
point
A
belongs
to
the
circle
Γ
with
center
point
I
and
radius
2
.
On
a
figure
(graphic
unit
1
cm
)
to
be
completed
as
the
exercise
progresses,
place
the
point
I
,
draw
the
circle
Γ
,
then
construct
the
point
A
.
2
Consider
the
rotation
r
with
center
point
I
and
angle
ı
2
.
Show
that
point
B
,
image
of
point
A
by
rotation
r
,
has
affix
:
z
B
=
−
1
+
i
·
3
+
1
Justify
that
the
point
B
belongs
to
the
circle
Γ
.
3
Calculate
the
affix
of
the
point
C
image
of
the
point
A
by
symmetry
of
center
I
.
4
What
is
the
nature
of
the
triangle
ABC
?
Justify.
E.3132
Parts
A
and
B
are
indepen-dent
Consider
the
equation
(
E
)
:
z
3
−
(4
+
i)
z
2
+
(7
+
i)
z
−
4
=
0
where
z
denotes
a
complex
number.
Part
A
1
a
Show
that
(
E
)
has
a
real
solution,
denoted
by
z
1
.
b
Determine
the
two
complex
numbers
a
and
b
such
that,
for
any
complex
number
z
,
we
have
:
z
3
−
(4+i)
·
z
2
+(7+i)
·
z
−
4
=
z
−
z
1
·
z
−
2
−
2i
·
az
+
b
2
Solve
(
E
)
.
Part
B
In
the
plane
equipped
with
a
direct
orthonormal
coordinate
system
O
;
−→
u
;
−→
v
,
consider
the
three
points
A
,
B
and
C
with
respective
affixes
1
,
2+2i
and
1
−
i
.
1
Represent
A
,
B
and
C
.
2
Determine
the
modulus
and
an
argument
of
2+2
i
1
−
i
.
De-duce
the
nature
of
triangle
OBC
.
3
What
does
line
(
OA
)
represent
for
triangle
OBC
?
Jus-tify
your
answer.
4
Let
D
be
the
image
of
O
under
the
rotation
by
angle
−
ı
2
with
center
C
.
Determine
the
affix
of
D
.
5
What
is
the
nature
of
OCDB
?
https://chingmath.fr
sacados/3820
sacados/3821
Extrait de France
Septembre 2010
chapExoCorrec/3132
sacados/3132
E.3120
The
complex
plane
is
referred
to
a
direct
orthonormal
reference
frame
O
;
−→
u
;
−→
v
.
The
points
introduced
in
the
text
(graphic
unit
:
2
cm
)
will
be
placed
on
the
same
figure,
which
will
be
completed
as
we
go
along
1
a
Solve
equation
:
(
E
):
z
2
−
2
3
·
z
+4=0
b
Consider
the
complex
numbers
:
z
1
=
3
+
i
;
z
2
=
3
−
i
And
we
denote
by
M
and
N
the
points
of
affixes
z
1
and
z
2
respectively.
Determine
the
modulus
and
argument
of
z
1
and
z
2
;
place
M
and
N
on
the
figure.
c
Determine
the
affixes
of
the
points
Q
and
P
respec-tive
images
of
M
and
N
by
the
vector
translation
−→
w
=
−
2
·
−→
u
.
Place
P
and
Q
on
the
figure.
Show
that
MNPQ
is
a
square.
2
Let
R
be
the
symmetrical
of
P
with
respect
to
O
,
E
the
image
of
P
by
the
rotation
of
center
O
and
angle
ı
2
,
S
the
image
of
E
by
the
homothety
of
center
O
and
ratio
3
.
Place
these
points
on
the
figure.
Calculate
the
affixes
of
R
and
S
.
Show
that
S
belongs
to
segment
[
MN
]
.
3
We
pose
:
a
=2
−
3
:
a
Show
that
:
1+
a
2
=4
a
;
1
−
a
2
=2
a
3
b
Express
the
affixes
Z
of
−→
PR
and
Z
of
−→
PS
in
terms
of
a
.
c
Show
that
:
⏐
⏐
Z
⏐
⏐
=
⏐
⏐
Z
⏐
⏐
;
Z
Z
=
e
i
π
3
d
Deduce
from
the
previous
questions
the
nature
of
the
triangle
PRS
E.3136
1
The
complex
plane
is
referred
to
a
direct
orthonormal
reference
frame
O
;
−→
u
;
−→
v
.
We
pose
:
a
=3
;
b
=5
−
2
·
i
;
c
=5+2
·
i
We
denote
by
A
,
B
and
C
the
points
with
affixes
a
,
b
and
c
respectively.
Let
M
be
a
point
of
affix
z
in
the
plane,
distinct
from
points
A
and
B
.
a
Show
that
ABC
is
an
isosceles
right-angled
triangle.
b
Give
a
geometric
interpretation
of
the
argument
of
the
complex
number
z
−
3
z
−
5+2
·
i
.
c
Then
determine
the
set
of
points
M
of
affix
z
such
that
z
−
3
z
−
5+2
·
i
is
a
strictly
negative
real
number.
2
Let
Γ
be
the
circumscribed
circle
of
the
triangle
ABC
and
Ω
the
point
with
affix
2
−
i
.
a
Give
the
complex
writing
of
the
rotation
r
of
center
Ω
and
angle
−
ı
2
.
b
Determine
the
image
Γ
of
Γ
by
the
rotation
r
.
Deter-mine
a
parametric
equation
of
Γ
.
E.3182
1
In
the
complex
plane
referred
to
an
orthonormal
refer-ence
frame
O
;
−→
u
;
−→
v
,
consider
the
points
:
A
of
affix
a
where
a
∈
R
;
B
affix
b
+i
where
b
∈
R
;
C
image
of
B
by
the
rotation
of
center
A
and
angle
ı
3
a
Determine
a
relationship
between
a
and
b
so
that
the
point
C
belongs
to
the
axis
O
;
−→
v
.
b
Then
express
the
affix
of
the
point
C
as
a
function
of
a
.
2
In
this
question,
we
pose
a
=
3
and
b
=0
.
Consider
the
points
C
of
affix
c
=
−
i
and
D
of
affix
d
=2+
3
−
2i
√
3
a
What
is
the
nature
of
the
triangle
ABC
?
b
Calculate
the
quotient
d
−
a
c
−
a
;
what
can
be
deduced
for
the
triangle
ACD
?
c
Determine
the
affix
of
the
point
E
image
of
D
in
the
rotation
of
center
A
and
angle
ı
3
.
d
Determine
the
affix
of
the
point
F
image
of
D
in
the
translation
of
vector
−→
AC
.
e
Determine
the
nature
of
the
triangle
BEF
.
E.3202
The
complex
plane
is
referenced
to
a
direct
orthonormal
O;;
−→
u
;
−→
v
.
The
graphic
unit
is
2
cm
.
Designate
by
i
the
complex
number
of
modulus
1
and
argu-ment
+
ı
2
.
We’ll
create
a
figure
and
complete
it
as
we
go
along.
1
Solve
in
the
set
C
of
complex
numbers
the
equation
z
−
4
z
=i
.
Write
the
solution
in
algebraic
form.
2
Solve
in
C
the
equation
z
2
−
2
z
+4=0
.
Write
the
solutions
in
exponential
form.
3
Let
A
,
B
,
A
and
D
be
points
in
the
complex
plane
with
affixes
:
a
=
2
;
b
=
4
;
a
=
2i
;
d
=
2
+
2i
What
is
the
nature
of
the
triangle
ODB
?
4
Let
E
and
F
be
the
points
with
respective
affixes
:
e
=
1
−
i
3
;
f
=
1
+
i
3
What
is
the
nature
of
the
quadrilateral
OEAF
?
5
Let
C
be
the
circle
of
center
A
and
radius
2
.
Let
C
‘
be
the
circle
with
center
A
and
radius
2.
Let
r
be
the
rotation
of
center
O
and
angle
+
ı
2
.
a
Let
E
be
the
image
of
point
E
under
rotation
r
.
Cal-culate
the
affix
e
of
point
E
.
b
Prove
that
point
E
is
a
point
on
circle
C
.
c
Verify
that
:
e
−
d
=
3+2
e
−
d
.
Deduce
that
points
E
,
E
and
D
are
collinear.
6
Let
D
be
the
image
of
point
D
under
rotation
r
.
Prove
that
triangle
EE
D
is
a
right
triangle.
https://chingmath.fr
chapExoCorrec/3120
sacados/3120
Antilles-Guyane
Septembre 1998
5 points
chapExoCorrec/3136
sacados/3136
chapExoCorrec/3182
sacados/3182
Antilles-Guyane
Juin 2006
5 points
chapExoCorrec/3202
sacados/3202
E.3855
For
each
of
the
following
six
state-ments,
indicate
whether
it
is
true
or
false
and
provide
a
justi-fication
for
your
answer.
An
answer
without
justification
will
not
earn
any
points.
The
complex
plane
is
related
to
an
orthonormal
direct
refer-ence
frame
O
;
−→
u
;
−→
v
.
1
Let
z
be
a
complex
number
with
argument
ı
3
.
Proposition
1:
ˇ
z
100
is
a
real
numberı.
2
Let
(
E
)
be
the
set
of
points
M
with
affix
z
different
from
1
in
the
plane
such
that
:
⏐
⏐
⏐
z
1
−
z
⏐
⏐
⏐
=
1
.
Proposition
2:
ˇthe
set
(
E
)
is
a
line
parallel
to
the
real
axisı.
3
Let
r
be
the
rotation
by
angle
−
ı
2
and
whose
center
K
has
affix
1+i
·
3
.
Proposition
3:
ˇthe
image
of
the
point
O
by
the
rota-tion
r
has
affix
1
−
3
+i
·
1+
3
ı
4
Consider
the
following
equation
(
E
)
:
z
2
+
2
·
ı
5
·
z
+
1
=
0
Proposition
4:
ˇThe
equation
(
E
)
has
two
complex
solutions
with
moduli
equal
to
1
.ı
3.
Annals
on
plane
configurations
E.4074
The
complex
plane
is
referenced
to
the
direct
orthonormal
coordinate
system
O
;
−→
u
;
−→
v
;
the
graphic
unit
is
1
cm
.
1
Solve
the
following
equation
in
the
set
of
complex
num-bers
:
z
2
+
4
·
z
+
8
=
0
Give
the
solutions
in
algebraic
form,
then
in
trigonomet-ric
form.
2
Let
A
and
B
be
the
points
on
the
plane
with
respective
affixes
:
a
=
2
−
2
·
i
;
b
=
−
a
Place
these
points
on
a
graph
that
will
be
completed
as
the
exercise
progresses.
a
Determine
the
affix
c
of
point
C
,
image
of
point
B
by
rotation
about
center
O
and
angle
ı
2
.
b
We
note
D
the
image
of
C
by
rotation
about
center
A
and
angle
ı
2
;
prove
that
the
affix
d
of
point
D
is
:
d
=
2
−
6
·
i
c
Place
the
points
C
and
D
on
the
graph.
What
is
the
nature
of
the
quadrilateral
ABCD
?
3
¸
being
a
non-zero
real
number,
we
denote
by
G
α
,
the
barycenter
of
the
system
:
(
A
;
1)
;
(
B
;
−
1)
;
(
C
;
¸
)
a
Express
the
vector
−−−→
CG
α
en
as
a
function
of
the
vector
−−→
BA
.
b
Determine
the
set
of
points
G
α
when
¸
décrit
the
set
of
non-zero
reals.
Construct
this
set.
c
For
what
value
of
¸
will:
G
α
=
D
?
4
It
is
assumed
in
this
question
that
¸
=2
.
In
this
question,
any
trace
of
research,
however
incom-plete,
or
of
unsuccessful
initiative,
will
be
taken
into
ac-count
in
the
assessment.
Determine
and
construct
the
set
of
points
M
of
the
plane
such
that
:
−−→
MA
−
−−→
MB
+
2
·
−−→
MC
=
4
·
2
E.3903
The
complex
plane
is
provided
with
a
direct
orthonormal
reference
frame
O
;
−→
u
;
−→
v
d
graphic
unit
2
cm
.
Consider
the
points
A
,
B
and
C
of
affixes
:
z
A
=
−
2
·
i
;
z
B
=
−
3
+
i
;
z
C
=
3
+
i
1
Écrire
z
A
,
z
B
et
z
C
sous
exponential
form.
2
Determine
the
center
and
radius
of
the
circle
Γ
passing
through
the
points
A
,
B
et
C
.
3
Make
a
figure
and
place
the
point
A
,
draw
the
circle
Γ
then
place
the
points
B
et
C
.
4
a
Write
the
quotient
z
B
−
z
A
z
C
−
z
A
sous
algebraic
form
and
then
in
exponential
form.
b
Determine
the
nature
of
the
triangle
ABC
.
5
We
note
r
the
rotation
of
center
A
and
angle
measuring
ı
3
radians.
a
Show
that
the
point
O
,
image
of
O
par
r
,
has
affix
−
3
−
i
.
b
Demonstrate
that
the
points
C
and
O
sont
diametri-cally
opposed
on
the
circle
Γ
.
c
Trace
the
image
Γ
of
the
circle
Γ
par
the
rotation
r
.
d
Justify
that
the
circles
Γ
and
Γ
se
intersect
at
A
et
B
.
6
a
Determine
the
set
(
E
)
des
points
M
d’affix
z
tels
that
:
|
z
|
=
⏐
⏐
z
+
3
+
i
|
b
Show
that
points
A
and
B
belong
to
(
E
)
.
https://chingmath.fr
chapExoCorrec/3855
sacados/3855
Extrait Liban
Juin 2008
chapExoCorrec/4074
sacados/4074
chapExoCorrec/3903
sacados/3903
ABCA’B’C’PQR
E.3217
In
the
oriented
plane
equipped
with
a
direct
orthonormal
reference
frame,
consider
ABC
a
direct
triangle
on
which
three
equilateral
triangles
are
con-structed
externally:
BCA
,
ACB
,
and
ABC
.
We
consider
the
points
P
,
Q
and
R
to
be
the
respective
centers
of
gravity
of
the
triangles
BCA
,
ACB
and
ABC
,
respectively:
We
note
a
,
b
,
c
,
a
,
b
,
c
,
p
,
q
and
r
the
respective
affixes
of
points
A
,
B
,
C
,
A
,
B
,
C
,
P
,
Q
and
R
.
1
a
Translate,
with
the
affixes
of
the
points
concerned,
that
C
is
the
image
of
A
by
a
rotation
whose
angle
and
center
will
be
specified.
b
Show
that
:
a
+
b
+
c
=
a
+
b
+
c
.
2
Deduce
that
:
p
+
q
+
r
=
a
+
b
+
c
.
3
Deduce
that
the
triangles
ABC
,
A
B
C
and
PQR
have
the
same
center
of
gravity.
4
Show
that
:
3(
q
−
p
)
=
(
b
−
c
)
+
(
c
−
a
)
+
(
a
−
b
)
.
We
will
admit
that,
similarly:
3(
r
−
p
)
=
(
a
−
c
)
+
(
b
−
a
)
+
(
c
−
b
)
.
5
Justify
the
following
equalities:
a
−
c
=e
i
π
3
(
b
−
c
)
;
b
−
a
=e
i
π
3
(
c
−
a
)
;
c
−
b
=e
i
π
3
(
a
−
b
)
6
Deduce
from
questions
4
and
5
that
the
triangle
PQR
is
equilateral.
E.3822
The
complex
plane
is
equipped
with
an
orthonormal
direct
reference
frame
O
;
−→
u
;
−→
v
(unit
1
cm
)
.
We
will
draw
a
figure
that
we
will
complete
as
we
go
along
with
the
questions.
We
consider
the
points
A
,
B
,
S
,
and
Ω
with
respective
affixes
:
a
=
−
2
+
4i
;
b
=
−
4
+
2i
s
=
−
5
+
5i
;
w
=
−
2
+
2i
Let
h
be
the
homothety
with
center
S
and
ratio
3
.
Let
C
be
the
image
of
point
A
under
h
and
D
be
the
image
of
point
B
under
h
.
1
a
Determine
the
complex
form
of
h
.
b
Show
that
point
C
has
affix
c
=4+2
i
and
that
point
D
has
affix
d
=
−
2
−
4
i
.
2
Show
that
points
A
,
B
,
C
,
and
D
lie
on
the
same
circle,
whose
center
and
radius
will
be
specified.
3
Demonstrate
that
line
(
S
Ω)
is
the
perpendicular
bisector
of
segment
[
AB
]
.
4
Let
P
be
the
midpoint
of
segment
[
AC
]
.
a
Determine
the
affix
p
of
point
P
.
b
Show
that
!
−
p
d
−
b
=
−
1
2
·
i
.
Use
this
to
figure
out
the
mea-sure
of
angle
−−→
BD
;
−→
P
Ω
.
5
Let
Q
be
the
midpoint
of
segment
[
BD
]
.
What
does
point
Ω
represent
for
triangle
PQS
?
4.
Annals
on
plane
transformations
E.3175
In
the
complex
plane
referred
to
a
direct
orthonormal
reference
frame
O
;
−→
u
;
−→
v
(graphic
unit
2
cm
)
,
consider
the
points
A
,
B
and
C
with
affixes
:
z
A
=
2
;
z
B
=
1
+
i
3
;
z
C
=
1
−
i
3
Part
A
1
a
Give
the
exponential
form
of
z
B
and
then
of
z
C
.
b
Place
points
A
,
B
and
C
.
2
Determine
the
nature
of
the
quadrilateral
OBAC
.
3
Determine
and
construct
the
set
D
of
points
M
of
the
plane
such
that
:
|
z
|
=
|
z
−
2
|
Part
B
To
any
point
M
of
affix
z
such
that
z
=
z
A
,
we
associate
the
point
M
of
affix
z
defined
by:
z
=
−
4
z
−
2
1
a
Solve
in
C
the
equation
:
z
=
−
4
z
−
2
.
b
Deduce
the
points
associated
with
B
and
C
.
c
Determine
and
place
the
point
G
associated
with
the
center
of
gravity
G
of
the
triangle
OAB
.
2
a
Course
question:
Prerequisite
:
the
modulus
of
any
complex
number
z
,
denoted
|
z
|
,
verifies
|
z
|
2
=
z
·
z
where
z
is
the
conjugate
of
z
.
Show
that
:
for
all
complex
numbers
z
1
and
zCOPY
01
2
:
⏐
⏐
z
1
×
z
2
⏐
⏐
=
⏐
⏐
z
1
⏐
⏐
×
⏐
⏐
z
2
⏐
⏐
.
for
any
non-zero
complex
number
z
:
⏐
⏐
⏐
1
z
⏐
⏐
⏐
=
1
|
z
|
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Septembre 2004
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sacados/3822
chapExoCorrec/3175
sacados/3175
b
Show
that
for
any
complex
number
z
distinct
from
2
:
⏐
⏐
z
−
2
⏐
⏐
=
2
|
z
|
|
z
−
2
|
c
It
is
assumed
in
this
question
that
M
is
any
point
of
D
,
where
D
is
the
set
defined
in
question
3
from
part
A
.
Show
that
the
point
M
associated
with
M
belongs
to
a
circle
Γ
whose
center
and
radius
will
be
specified.
Trace
Γ
.
E.3156
The
plane
is
referred
to
a
direct
orthonormal
coordinate
system
O
;
−→
u
;
−→
v
(graphic
unit
:
1
cm
)
.
Part
A
In
the
reference
frame
O
;
−→
u
;
−→
v
,
consider
the
curve
H
of
equation
:
y
2
−
x
2
=16
.
1
Show
that
H
is
the
union
of
two
curves
C
and
C
where
C
is
the
representative
curve
of
the
function
f
defined
on
R
by
f
(
x
)=
x
2
+16
and
where
C
is
the
image
of
C
by
a
simple
transformation
to
be
specified.
2
a
Study
the
function
f
(limits
at
the
bounds
of
the
defining
set
and
direction
of
variation)
.
b
Show
that
the
straight
line
of
equation
y
=
x
is
an
asymptote
of
C
.
c
Draw
H
in
the
reference
frame
O
;
−→
u
;
−→
v
.
We
name
A
and
B
the
points
on
the
curve
with
abscis-sas
−
3
and
3
respectively.
Consider
the
domain
D
of
the
plane
made
up
of
the
points
M
(
x
;
y
)
verifying:
−
3
x
3
;
x
2
+
16
y
5
Hatch
the
domain
D
and
express
the
area
of
D
using
an
integral
that
we
won’t
attempt
to
calculate.
Part
B
We
call
r
the
rotation
of
center
O
and
angle
−
ı
4
.
1
a
Give
the
complex
writing
of
r
.
b
Denote
by
x
and
y
the
coordinates
of
the
point
M
,
image
of
the
point
M
(
x
;
y
)
in
the
plane.
Check
that
:
x
=
1
2
·
(
x
+
y
)
y
=
1
2
·
(
−
x
+
y
)
Determine
the
coordinates
of
points
A
and
B
,
respec-tive
images
of
A
and
B
by
rotation
r
.
Place
the
points
A
and
B
in
the
reference
frame
O
;
−→
u
;
−→
v
.
2
Let
H
be
the
hyperbola
of
equation
:
x
·
y
=
8
.
a
Trace
H
in
the
reference
frame
O
;
−→
u
;
−→
v
.
b
Show
that
H
is
the
image
of
H
by
rotation
r
.
3
Let
D
be
the
image
of
D
by
rotation
r
.
We
admit
that
D
is
the
set
of
points
M
(
x
;
y
)
of
the
plane
verifying:
2
x
4
·
2
;
8
x
y
5
·
2
−
x
.
a
Chop
D
.
b
Calculate
the
area
of
D
,
expressed
in
cm
2
.
Deduce
an
approximate
value
to
the
nearest
10
−
3
of
the
area
of
D
.
5.
Autes
annales
E.3901
The
plane
is
equipped
with
a
di-rect
orthonormal
reference
frame
O
;
−→
u
;
−→
v
.
Let
A
,
B
,
and
P
be
the
respective
affix
points
:
a
=
5
+
5
·
i
;
b
=
5
−
5
·
i
;
p
=
10
Consider
a
point
M
,
distinct
from
O
,
with
affix
z
.
We
denote
U
the
point
with
affix
u
,
image
of
the
point
M
by
the
rotation
R
A
with
center
A
and
angle
of
measurement
−
ı
2
.
We
denote
T
the
affix
point
t
,
image
of
point
M
by
rotation
R
B
with
center
B
and
angle
of
measurement
ı
2
.
Let
D
be
the
image
of
point
M
by
the
symmetry
of
center
O
.
1
Demonstrate
that
the
affix
of
point
U
is
u
=i(10
−
z
)
;
ex-press
in
terms
of
z
the
affix
of
point
T
then
justify
that
quadrilateral
MUDT
is
a
parallelogram
with
center
O
.
2
Determine
the
set
Γ
of
points
M
with
affix
z
such
that
:
z
·
z
−
5
·
z
−
5
·
z
=
0
Justify
that
the
quadrilateral
OAPB
is
inscribed
in
Γ
.
3
We
assume
that
point
M
is
distinct
from
O
,
A
and
P
.
Points
O
,
M
,
and
U
are
therefore
distinct
from
each
other
in
pairs.
a
Prove
that
points
O
,
M
and
U
are
collinear
if,
and
only
if
:
u
z
=
u
z
b
Prove
that
points
O
,
M
and
U
are
collinear
if,
and
only
if,
M
belongs
to
Γ
.
4
Determine
the
set
of
points
M
on
the
plane
such
that
OMU
is
an
isosceles
triangle
at
O
.
What
is
the
nature
of
the
quadrilateral
MUDT
in
this
case?
5
Determine
the
set
of
complex
numbers
z
such
that
u
z
is
purely
imaginary.
Deduce
the
nature
of
the
quadrilateral
MUDT
in
the
case
where
M
is
a
point
on
the
line
(
OP
)
devoid
of
O
and
P
.
Finally,
prove
that
there
is
a
unique
position
of
the
point
M
such
that
MUDT
is
a
square.
6.
Unclassified
financial
years
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E.4236
The
complex
plane
is
referenced
to
O
;
−→
u
;
−→
v
orthonormal
direct.
Consider
the
point
I
of
affix
i
and
the
point
A
of
affix
z
A
=
√
3+2
·
i
1
Show
that
the
point
A
belongs
to
the
circle
Γ
with
center
point
I
and
radius
2
.
2
Consider
the
rotation
r
with
center
the
point
I
and
angle
ı
2
.
Show
that
the
point
B
image
of
the
point
A
by
the
rota-tion
r
has
affix
:
z
B
=
−
1
+
i
·
3
+
1
Justify
that
the
point
B
belongs
to
the
circle
Γ
.
3
Calculate
the
affix
of
the
point
C
,
image
of
the
point
A
by
central
symmetry
of
the
point
I
.
4
What
is
the
nature
of
the
triangle
ABC
?
Justify.
E.4248
The
complex
plane
is
referred
to
a
reference
frame
O
;
−→
u
;
−→
v
orthonormal
direct
Consider
the
points
A
and
B
with
respective
affixes
:
a
=
i
;
b
=
1
+
i
Note:
r
A
the
rotation
with
center
A
and
angle
ı
2
;
r
B
the
rotation
of
center
B
and
angle
ı
2
;
r
O
the
rotation
of
center
O
and
angle
−
ı
2
.
Consider
:
the
point
C
of
affix
c
=3
·
i
;
the
point
D
image
of
C
by
r
A
;
point
G
image
of
D
by
r
B
;
point
H
image
of
C
by
r
0
.
Let
d
,
g
and
h
be
the
respective
affixes
of
the
points
D
,
G
and
H
.
1
Demonstrate
that
d
=
−
2+i
.
2
Determine
g
and
h
.
3
Demonstrate
that
the
quadrilateral
CDGH
is
a
rectan-gle.
E.3859
The
complex
plane
is
referred
to
a
reference
frame
O
;
−→
u
;
−→
v
orthonormé.
Let
(
C
)
the
circle
with
center
O
et
and
radius
1
.
Consider
the
point
A
of
(
C
)
d
of
affix
:
z
A
=
e
i
·
π
3
1
Determine
the
affix
z
B
du
point
B
image
of
A
par
the
rotation
of
center
O
et
of
angle
2
ı
3
.
Determine
the
affix
z
C
of
point
C
image
of
B
par
the
rotation
of
center
O
et
of
angle
2
ı
3
.
2
a
Justify
that
(
C
)
est
the
circumscribed
circle
of
the
triangle
ABC
.
Construct
the
points
A
,
B
and
C
on
the
sheet
of
graph
paper.
b
What
is
the
nature
of
the
triangle
ABC
?
Justify.
3
So
h
the
homothety
of
center
O
and
ratio
−
2
.
a
Complete
the
figure
by
placing
the
points
P
,
Q
et
R
images
respective
of
the
points
A
,
B
et
C
par
h
.
b
What
is
the
nature
of
the
triangle
PQR
?
Justify.
4
In
this
question,
the
candidate
is
invited
to
write
on
his
copy
the
steps
of
his
approach
even
if
it
does
not
succeed
.
a
Give
the
complex
writing
of
h
.
b
Calculer
z
A
+
z
B
+
z
C
.
Deduce
that
A
is
the
middle
of
segment
[
QR
]
.
c
What
can
be
said
of
the
straight
line
(
QR
)
in
relation
to
the
circle
(
C
)
?
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E.3968
Part
1:
Organized
restitution
of
knowledge
The
complex
plane
is
referred
to
a
O
;
−→
u
;
−→
v
orthonormé
direct
reference
frame.
Prerequisites:
Remember
that
the
complex
writing
of
a
direct
similitude
in
the
plane
is
of
the
form
z
=
¸
·
z
+
˛
,
where
¸
est
is
a
non-zero
complex
number
and
˛
est
is
a
complex
number.
Let
A
,
B
,
C
,
D
quatre
points
of
the
plane
;
on
the
one
hand,
assume
that
the
points
A
et
C
sont
distinct
and,
on
the
other
hand,
that
the
points
B
et
D
sont
distinct.
Show
that
there
is
a
single
direct
similitude
such
that
:
s
(
A
)
=
B
;
s
(
C
)
=
D
Part
2:
The
complex
plane
is
referred
to
the
reference
frame
A
;
−−→
AB
;
−−→
AD
orthonormal
direct
such
that
:
−−→
AB
;
−−→
AD
=
ı
2
[2
·
ı
]
Consider
point
C
such
that
ABCD
is
a
square.
Let
E
be
the
midpoint
of
segment
[
AD
]
,
we
consider
the
square
EDGF
such
that
:
−−→
ED
;
−−→
EF
=
ı
2
[2
·
ı
]
.
1
a
Draw
a
figure
by
placing
the
points
A
,
B
,
C
,
D
,
E
,
F
,
G
.
The
figure
will
be
completed
during
the
exercise.
b
Specify
the
complex
numbers
a
,
b
,
c
,
d
,
e
,
f
,
g
,
respec-tive
affixes
of
points
A
,
B
,
C
,
D
,
E
,
F
and
G
.
c
Show
that
there
is
a
unique
direct
similarity
s
of
the
plane
such
that
:
s
(
D
)
=
F
;
s
(
B
)
=
D
2
We
propose
to
specify
the
characteristic
elements
of
di-rect
similarity
s
.
a
Determine
the
ratio
k
and
angle
„
of
the
direct
simi-larity
s
.
b
Give
the
complex
form
of
this
similarity.
c
Determine
the
center
Ω
of
the
direct
similarity
s
.
E.3128
The
plane
is
referenced
to
O
;
−→
u
;
−→
v
direct
orthonormal
(graphic
unit
2
cm
)
.
The
figure
will
be
completed
as
the
exercise
progresses.
Let
I
be
the
point
with
affix
2i
.
We
call
f
the
transformation
which,
to
any
point
M
of
affix
z
associates
the
point
M
of
affix
z
such
that
z
=i
·
z
.
1
a
Specify
the
nature
of
f
and
its
characteristic
ele-ments.
b
Determine
the
affix
of
the
point
A
,
image
by
f
of
the
point
A
of
affix
1+
2+i
.
c
Show
that
the
points
A
,
I
and
A
are
aligned.
2
a
Show
that
the
set
(Γ)
of
points
M
of
the
plane
such
that
M
,
I
and
M
are
aligned,
is
the
circle
with
center
Ω
of
affix
1+i
and
radius
2
.
b
Verify
that
the
point
A
belongs
to
(Γ)
.
c
Determine
the
set
(Γ
)
described
by
the
point
M
when
the
point
M
describes
(Γ)
.
3
Let
B
be
the
point
with
affix
2+2i
and
B
be
the
image
of
B
by
f
.
a
Demonstrate
that
the
straight
lines
(
AB
)
and
(
A
B
)
are
perpendicular.
b
Let
C
be
the
point
of
intersection
of
the
lines
(
AB
)
and
(
A
B
)
.
Determine
the
nature
of
the
quadrilateral
OACA
.
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chapExoCorrec/3968
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