P 的速度为 2cm/s, Q的速度为3cm/s
AP = 2t, CQ = 3t, DQ = 6-3t, AP=DQ时, 2t=6-3t, t = 6/5
S-PQH = 1/2 AD * HQ = 4 (DQ-AP) = 4 (6-5t), t = 1时, S = 4
P 的速度为 2cm/s, Q的速度为3cm/s
AP = 2t, CQ = 3t, DQ = 6-3t, AP=DQ时, 2t=6-3t, t = 6/5
S-PQH = 1/2 AD * HQ = 4 (DQ-AP) = 4 (6-5t), t = 1时, S = 4