Feuille 2 bis : Trigonométrie

R2(O,~ i,~ j)
~u = (3,1) ~v = (−2,2) π
4
~u ~v O (
~
i0,~ j0)
~
i0,~ j0
~u ~v
(
~
i,~ j)~u
z1=√6 + i√2, z2=√3 + i√3.
z1z2
z1z2
z1z2
5π
12
π
12 z1/z2
I
sin(2x) + sin(7x)=0 I=−π
5,π 5
sin(3x) = cos(2 −3x)I= [0, π[
cos(3x−
π
6) + cos(x−
2π
3)=0 I=−π 4,π 4
R2(O,~ i,~ j)
~u = (3,−3)
~v = (−8,0)
sin3(x)
cos2(x) sin2(x)
cos(2x) sin3(x)