00 TIC)CHUNG MINH BE.EH =CE.EDHAI TAM GIAC VUONG DEH VLLBEC C65EJI =...

1,00 tI

c)

ChUng minh BE.EH

=

CE.ED

Hai tam giac vuong

DEH

vll

BEC

c6

5EJi

⁼

BEe

^{(d6i dinh)}

0,25 d

Suy ra

I:1DEH

==

I:1BEC (g.g)

Dod6

DE =EH

9

BE

EC

Suy ra

BE.EH

=

CE.ED (dpcm).

0.50 tI

d)

Tim tt}p

h(Yp

cae diem H

Ta c6

BD

=

2 (khong dbi),

00

=

90° .

Do d6 khi

E

di chuyen tren c(lnh

CD

thi diem

H

ch~y tren du<'m.gtron

du<'m.gkinh

BD

(eung lIng vai diiy

CD).

HUUng dOn cham

tM

^kiim

^Ira

^{hpc ki}

^2,

^{mon Toan}

^lOp

^9,

nom hpc 2012-2013

- Tr 3