Bonjour, j’aimerai savoir si l’exo 3 est bon et si vous pouvez m’expliquer comment faire le 4?

Bonsoir,

5π/4 ≡ 3π/4 [2π]
D'où cos(5π/4) = cos(3π/4) = -(√2)/2

14π/3 ≡ 2π/3 [2π]
D'où tan(14π/3) = tan(2π/3) = sin(2π/3)/cos(2π/3) = ((√3)/2)/(-1/2) = -√3

-43π/6 ≡ 5π/6 [2π]
D'où sin(-43π/6) = sin(5π/6) = 1/2