a - 2 = 0, a = 2
b - 3 = 0, b = 3
4 - c = 0, c = 4
A(1, √2), B(4, √2), C(2, √2), 三者在同一条直线上(题中叙述似乎有问题)
t秒: M(1 + 2t, √2), N(4+t, √2)
MN = 1 = 4 + t - (1 + 2t) = 1, t = 2, M(5, √2), △OCM的面积 = (1/2)(5-2)*√2 = 3√2/2
或
MN = 1 = 1+ 2t - (4 + t), t = 4, M(9, √2), △OCM的面积 = (1/2)(9-2)*√2 = 7√2/2