The curve xy+λ=0 passes through the point (2,−2λ), where λ is a non-zero real constant.
(i) Calculate dxdy at a general point on the curve.
(ii) Determine the value of λ for which the tangent at the point with x-coordinate 2 has slope 3.
(iii) For the value of λ obtained in part (ii), write the equation of the corresponding tangent.