'''
Identitee remarquable
(cos a)**2+(sin a)**2 =1
-1 <= cos(x) <= 1
-1 <= sin(x) <= 1
____________________________
Angles remarquables
- cos(0)=1
sin(0)=0
- cos(π/6)=(√3)/2
sin(π/6)=1/2
- cos(π/4)=(√2)/2
sin(π/4)=(√2)/2
- cos(π/3)=1/2
sin(π/3)=(√3)/2
- cos(π/2)=0
sin(π/2)=1
- cos(π)=-1
sin(π)=0
- cos(3π/2)=0
sin(3π/2)=-1
____________________________
liste angle (sens trigo)
0, π/6, π/4, π/3, π/2
2π/3, 3π/4, 5π/6, π
7π/6, 5π/4, 4π/3, 3π/2
5π/3, 7π/4, 11π/6, 2π
'''