2018年怀柔区初三数学一模试题及答案解析word - 百度文库 ر

ݷʱ : 2024/12/24 20:50:13һ µȫĶ

ʽ

(2)B(43) 3

2

(3)y=mx-4mx+4m-1(m0)yύڵA0,3, 4n-1=3.

n=1. 4

2ߵıʽΪy?x?4x?3.

1x?m?x2?4x?3. 21ɡ=0: m??5

16

2y?x?4x?3xĽCΪ1,0

CyĶԳƵC1Ϊ-1,0.

11x?mãm?.6 221ѣ-4,3y?x?mãm?5.

211mȡֵΧm??m 5. 7

162ѣ-1,0y? 27.

(1)ͼ 1

A

(2) ߶ADƵAʱ뷽ת90㣬õ߶AE. DAE=90㣬AD=AE. DAC+CAE =90. ߡBAC=90, BAD+DAC =90.

BAD=CAE . 2 ֡AB=AC,

AEBDCABDաACE. B=ACE.

EߡABCУA=90㣬AB=AC,

BB=ACB=ACE=45.

ѧϰð

DCHF ʽ

ECD=ACB+ACE=90. 4 (3).DE,ڡADEΪֱΣԿDE=25 .ɡADF=60,CAE=7.5㣬EDCĶ͡CDFĶӶ֪DFij 6 .AAHDFڵHRtADH, ɡADF=60㣬AD=1AHDHij . DFDHijHFij

. RtAHF, AHHF,ùɶAFij7 28.

(1)P12,0P20,22 ͼ y=x+bϣڡOġ㡱POֱy=x+bľm2. ֱy=x+b1yڵEOOHֱy=x+b1ڵH. ΪOH=2RtDOEУ֪OE=22. ɵb1=22.ͬɵb2=-22.

bȡֵΧ:?22b22. 6 (2)x>3 x??3. 8

Hy43E21DC4C3C2C1OC1C2C3C412y=x+b234xy=x+b1 ѧϰð