As shown in the figure, P is the point on the fixed length line AB, C and d start from P and B respectively and move to the left along the straight line AB at the speed of 1cm / s and 2cm / s, C is on the line AP, (C is on the line AP, D is on the line BP) when C and d move to any time, there is always PD = 2Ac, then AP / AB equals () a.1/2 b.1/3 c.1/4 d.1/5. (2) under the condition of (1), q is a point on the line AB, and aq-bq = PQ, find the value of PQ / ab

As shown in the figure, P is the point on the fixed length line AB, C and d start from P and B respectively and move to the left along the straight line AB at the speed of 1cm / s and 2cm / s, C is on the line AP, (C is on the line AP, D is on the line BP) when C and d move to any time, there is always PD = 2Ac, then AP / AB equals () a.1/2 b.1/3 c.1/4 d.1/5. (2) under the condition of (1), q is a point on the line AB, and aq-bq = PQ, find the value of PQ / ab

1. Because there are always two points PD = 2Ac, C and D moving to the left along the straight line AB at the speed of 1cm / s and 2cm / s respectively from P and B, that is, DB = 2cp, then there are always Pb = 2AP, so AP / AB is equal to 1 / 3. Under the condition of B2 and (1), q is a point on the line AB, and aq-bq = PQ, that is, AQ =