Bonjour,
Sur R :
sin(3x - π/4) = sin(2y)
⇔ 3x - π/4 = 2y + k2π ou 3x - π/4 = π - 2y + k2π
⇔ y = 3x/2 - π/8 - kπ (1) ou y = -3x/2 + π/8 + kπ (2)
x + y = π/2 ⇔ y = π/2 - x (3)
(1) et (3) ⇒ π/2 - x = 3x/2 - π/8 - kπ
⇔ 5x/2 = π/2 + π/8 + kπ
⇔ 5x/2 = (5 + 8k)π/8
⇔ x = (5 + 8k)π/10
⇔ x = π/2 + 4kπ/5 ⇒ y = ...
(2) et (3) ⇒ π/2 - x = -3x/2 + π/8 + kπ
⇔ x/2 = -π/2 + π/8 + kπ
⇔ x/2 = (-3 + 8k)π/8
⇔ x = (-3 + 8k)π/4
⇔ x = -3π/4 + 2kπ ⇒ y = ...