(ⅱ)f(θ)= | MN | min = | LK | = | LA |-| AK | = sinθ+cosθ-2 cosθ= sinθ-cosθ= .
From < θ < 0 < f (θ) < 1。
(iii) Let point M be the moving point on trajectory P, point N be the moving point on circle A, and let the maximum value of |MN| be g(θ) to find the value range of g(θ).
18. Syndrome: Left = (L2+A2) (L2-A2) (L2+B2) (L2+C2) = (A2+B2+C2+A2) (B2+C2+B2)