As shown in the figure, line AB = a, O is the point on line AB, C and D are the midpoint of line OA and ob respectively 1. Find the length of CD; 2. If point O is on the extension line of AB, please draw a graph and explain

As shown in the figure, line AB = a, O is the point on line AB, C and D are the midpoint of line OA and ob respectively 1. Find the length of CD; 2. If point O is on the extension line of AB, please draw a graph and explain

1. Because points c and D are the midpoint of line OA and ob respectively, so OC = 1 / 2oa, OD = 1 / 2ob, so CD = OC + od = 1 / 2 * OA + 1 / 2 * ob = 1 / 2 (OA + OB) = 1 / 2Ab, because ab = a, so CD = 1 / 2A2

As shown in the figure, line AB = 4, point O is a point on the extension line of line AB, and C and D are respectively the midpoint of OA OB to find CD

CD=OC-OD=1/2(OA-OB)=1/2AB=2

As shown in Figure 1, e and F are two moving points on the line AC, and de ⊥ AC is at e, BF ⊥ AC is at F, if AB = CD, AF = CE, BD intersects AC at point M
(1) To prove: MB = MD, me = MF; (2) when E and f move to the position as shown in Figure 2, other conditions remain unchanged, can the above conclusion be true? If yes, please give proof; if not, please give reasons

(1) Connect be, DF. ∵ de ⊥ AC to e, BF ⊥ AC to F, ∵ Dec = ∠ BFA = 90 ° de ∥ BF, in RT △ Dec and RT △ BFA, ∵ AB = CDAF = CE & nbsp; In this paper, we present a new method to connect be, DF. ≌ de ≌ RT ≌ BFA (HL), ≌ de = BF. ≌ quadrilateral BEDF is a parallelogram. ≌ MB = MD, me = MF; (2) yes. Connect be, DF. ≌ de ⊥ AC to e, BF ⊥ AC to F, ∤ Dec = ∠ BFA = 90 °, de ∥ BF. In RT ≌ Dec and RT △ BFA, ∥ AB = CDAF = CE & nbsp; In this paper, we present a new method for the determination of BFA (HL) and BFA (HL)

As shown in the figure, in the plane rectangular coordinate system, the three vertices of △ ABO are a (2,0) B (0,3) C (0,0), and the length of line AB is calculated

OA=2,OB=3,
AB=√(OA^2+OB^2)=√13.