dz = dz/dx * dx + dz/dy * dy dz/dx = ((x - y)^3 + x^(1/2) * sin y^2 + x * y)'_x = = 3 * (x - y)^2 + 1/2 * x^(-1/2) * sin y^2 + y dz/dy = ((x - y)^3 + x^(1/2) * sin y^2 + x * y)'_y = = -3 * (x - y)^2 + x^(1/2) * cos y^2 * 2y + x Тогда dz = (3 * (x - y)^2 + 1/2 * x^(-1/2) * sin y^2 + y) dx + + (-3 * (x - y)^2 + 2 * x^(1/2) * y * cos y^2 + x) dy