1、 1 38 “ ” “ ” “ ” 1 1 E ABCD AD P B BE ED DC C Q B BC C 2cm/s P Q t s BPQ y cm 2 y t 2 A AE=12cm B sin EBC= 7 4C 0 t 8 2 5 16 yt D t=9s PBQ D A BC=16cm ED=4cm AE=AD ED=BC ED=16 4=12cm 2 D t=9s Q C P ED N 3 NB NC AN=14 ND=2 NB= 809 2 NC= 41 4 BC=16 BCN PBQ D 2 C 1 2 3 2 y ax bx = + + 0 a A 1 0 B 3 0
2、1 C 1 C 2 1 C 1 AC C 2 A C D E F C 1 x DEF EF F 3 2 2 M BC EN EM BF N P MN M B C tan ENM M C P 3 1 2 13 22 y x x C 1 2 2 F 3 6 3 tan ENM=2 10 2 1 C 1 2 3 2 y ax bx = + + 0 a A 1 0 B 3 0 3 0 2 3 9 3 0 2 ab ab 1 2 1 a b C 1 2 13 22 y x x 2 13 22 y x x = 2 1 ( 1) 2 2 x C 1 2 2 1 CH x H A 1 0 C 1 2 AH=C
3、H=2 CAB= ACH=45 AC 1 yx DEF EF DEF=45 DEF= ACH 4 EF y DE=AC=22 EF=4 F m 2 13 22 mm E m m+1 2 13 ( 1) ( ) 4 22 m m m m 3 F 3 6 P P 1 P 2 3 BCEG GP 2 =CP 2 EP 2 =BP 2 EGN ECB EN EG EB EC EC=42 EG=BC=22 EB= 2 10 22 2 10 4 2 EN EN= 10 P 1 P 2 BEN P 1 P 2 = 1 2 EN= 10 2 M C P 10 2 3 Rt ABC C=90 AC=8 BC=6
4、 P 1 A C Q 2 A B C C P Q t 1 P Q 5 2 t ABC PQ S t 3 P Q t PQC t 5 2.24 1 35 2 S= 2 2 3(0 5) 5 16 40 (5 8) tt t t t 3 t= 16 5 t= 40 11 t=3.4 1 1 Q QE AC E PQ ABC AQE AQ AE QE AB AC BC PE= 3 5 t QE= 6 5 t PQ= 35 5 t Q B PQ t=5 PQ 2 3 2 CQ PQ CQ=CP PQ=CQ PQ=PC 1 1 Q QE AC E PQ C=90 QE BC ABC AQE AQ AE
5、QE AB AC BC AQ=2t AP=t C=90 AC=8 BC=6 AB=10 2 10 8 6 t t PE QE PE= 3 5 t QE= 6 5 t 2 2 2 PQ QE PE PQ= 35 5 t Q B PQ t=5 PQ =35 2 1 ABC PQ = AQP S Q AB S= 1 2 AP QE= 16 25 tt = 2 3 5 t 0 t 5 Q BC ABC PQ =S ABQP 6 S ABQP =S ABC S PQC = 1 2 8 6 1 2 8 t 16 2t = 2 16 40 tt 5 t 8 t ABC PQ S t S= 2 2 3(0 5
6、) 5 16 40 (5 8) tt t t t PQ=PC 35 5 t =8 t t=6 5 10 3.4 t= 16 5 t= 40 11 t=3.4 PQC 4 ABCD DC AB DA AB AD=4cm DC=5cm AB=8cm P B BC C Q A AB B 1cm/s P C PQ t s 1 t P Q 2 PQB S t S 7 3 PQB t 1 5 2 t=4 S 32 5 3 t= 40 11 t= 48 11 t=4 1 BC AB BC 2 PQB QB t t S 3 PQ=PB PQ=BQ QB=BP 3 cos B= 3 5 BE FB BC BP BF= 3 5 t QF=AB AQ BF= 8 8 5 t QP= 22 QF PF = 22 84 (8 ) ( ) 55 tt = 2 18 44 55 tt PQ=PB PF QB BF=QF BQ=2BF 3 82 5 tt t= 40 11 PQ=BQ 2 18 44 55 tt =8 t 2 11 48 0 tt 1 0 t 2 48 11 t QB=BP 8 t=t t=4 t= 40 11 t= 48 11 t=4 PQB 8 9
