0 <= x <= 2 x^2 <= y <= 4
∬[D] f(x, y) dA = ∫[0, 2] ∫[x^2, 4] f(x, y) dy dx
= ∫[0, 2] [∫[x^2, 4] f(x, y) dy] dx
= ∫[0, 2] [∫[x^2, 4] f(x, y) dy] dx = ∫[0, 2] [F(x, 4) - F(x, x^2)] dx
где F - первообразная от f(x, y) по y.
= ∫[0, 2] [F(x, 4) - F(x, x^2)] dx