/
Trueng THPT
Nglly~n Hll~
TB toan
DE THI
HQC KY I
Mon: Toan-KhBi 10 -Nam hoc 2014-2015
Thai gian: 90 phut
Call 1(1.5diim) Giai cac phuong trinh sau:
1. 12x + 31 = Ix - 21 ;
2.
-V'X2
+ 1 = x2
-
1 (HD: d~t fin phu).
Cau2(1.5diim)
Cho phuong trinh sau:
x - 3x + 2m - 1 = 0 (1)
1. Tim t~t ca cac gia tri cua tham s6 m dS phuong trinh (1)
co nghiem.
2. Tim t~t ca cac gia tri cua tham s6 m dS plnrong trinh (1)
.~ XlIX
co, l'rai ng 1uem
sao c110 A =X12 + Xl Z - Xl'2 Xz2 d at
Z
2
gia tri 16n nh~t.
Call 3(1.5diim) Giai he phuong trinh sau:
fX+ y -xy = 1
2
+ ,2 + 5(x + Y)
Call 4(1diem) Cho h~ plnrong trinh sau:
tx
.mx
{
+ 4y
x +my
=2
=2
=
6
+ In
..
Tim t~t ca cac gia tri cua tham s6 m dS h~ phuong trinh co
vo s6 nghiem.
Call 5(2didm) Trong m~t phang toa d9 Oxy cho A(-1;2), B(4;3)
1. Tim toa d9 diSm M thoa h~ thirc 3AM - 2Bf,l
=0.
2. Tim tren true Ox diem N sao cho tam giac NAB vucng tai
N.
Call 6(2didm) Cho tam giac ABC co
A
=
1200, AB=7 va AC=4.
G9i I la Him dirong tron n9i tiep cua tam giac ABC.
1. Tinh tich vo huong AB .AC;
2. Tinh d9 dai canh BC va ban kinh duong tron ngoai ti~p
tam giac IBC.
Call 7(O.5didm) Chox, y» Ovax+y=3. Chirng minh : X.y2 < 4.
I
I Call
Loi giai
i
1)12x+31= Ix_21~[2X+3=X-2
.2x
Can
1
1.5i1
1.5i1
+ 1 = x2
2) .Jx2
- 1
PT dacho c 0 dang:
V6i
Can
2
~.[X=-5
x
t
=
2 ¢=} ..,/x2
3x + 2m-l
-
.
0.75
./£1. + 1 = x2
+1-
¢::> ••
e· ., t -2=0~
+ 1=2~
[t _ -1
t-2
= 3 ¢:::> x =
x2
B~t t=../x1. + 1, BK t~ 0
2.
0.25
(lo'iti)
±-/3.
.
V~y PT co hai nghiem x
=±-/3
xrx~
(xl
f
+ sex + y) = 6
¢:::>
x
l(x
+y
+ y)2
0.25
+ 5(x + y} = 6
- 2xy
+ 5S = 6
+ V6i S=I va P=O: x, y Ia hai nghiem cua PT
Do do
0.25
- xy = 1.
B-tS
+ 'P
H"tr'th'nhfS-P=1.
~ =x y va =xy. v (J a l52 _ 2P
1.5i1
1
-x;' x;
xy = 1.
+:v2
0.5
= 0 (1)
1) Phuong trinh (1) co nghiem ¢::} ts> 0 ~ :13 - 8m > 0 ¢::} m ~ 13/8
2) Dk Phuong trinh (1) co nghiem: 1'n < 13:/8
A=x~ +X~ = (Xl + x2? - 2X1X2
= -4m2 + 10
Vi A~10 nen A Ian nhat khi m=O (thoa dk).
fX + y -
Can
3
= -1/3
.
V~y PT co hai nghi~m [; ~ =~/3
•
x2
+ 3 = -x + 2
X2 - X
~
=0
0.5
{P=S-1
S2 _ 3S ¢::} ~
~
0.5
4 =0
~
(x = 0
(x =:1
br = 1ho~c 1y = 0
+ 4X -
+ V6i S=-4 va P=-5: x, y la hai nghiem cua PT X2
5 = 0 ~ f'X :=-5
0.5
. X=l
Do do x = -15hoac f x = 1.-(y =
. ty =-::.
. Vay he co c nghiem CO;1),(1;O}.(-S;1),(1~-5).
f.
r:
(Neil thiiu kit luiin -0,25)
+ 4Y. = 2 + m
Can
4
Iii
x+m:y=2
+ D = m2 - 4''ill:.
D
+ H~ co vo
=
m - 2'':Y D
s6 nghiem
khi D
= m2
= DX'
=
2m - 8
0.5
o; = 0 ¢:? m=2
0.5
T'
A( -1; 2),B( 4; 3)
•
1) G01 M(x;y):
Can
--
----;t
{3(X
-')
3AM - 2BM = 0
¢::>
V~y M(-II ;0).
2) GOi N(x;O)E Ox. NA = (-1 - x; 2);
5
!J.NABvllong tai N khi
2i1
NA.NB
NB = (4 -
= 0 ¢:} (-1¢:>
A
Can
6
= 1200 , AB=7
+ 1) -
2(x - 4)
=
0
3(y _ 2) _ 2(y- 3) = 0
x2
-
¢:}
fx = -11
ly = 0
x; 3)
x)(4 - x)
3x
+2=0
.
1
0.5
+ 6= 0
~ x = 1 Vx
0.5
=2
va AC=4
1) "AlrifC = AB.AC.cosA =
4.7.( -D = -14
1
ea
2) *Tinh dQ dai canh BC:
BC2 = AB2 +AC2 -:-2AB_AC .cosA' = 93.
V~y BC = -J93
\.1
-:.
i;!!,
,* Tinhban
kinh duong tron ngoai !i~p }am giacIlst,"
', '; Trong MBC : fj
r
J '\
'/j!i,:·l .·
. Trong
!1lBC :
+ C = 60° =?!!. +£
f = 1800 _.~ +2;)
2
= 30° .
0.25'
1500C Do I Ia tam dirong tron nQi ti€p
i
,~!
,: ';"":" , : MBC)
~:'
0.5
1 7.'
'
Khi d6 2R fBC=
;.
~c~::::}R!Be = 4'93
sm.1
Chox, y> O va x+y=S. Clnrng minh : X.y2
Can
7
O.5d
Ta c6 :
3 =x
x-y2
¢::} -
+. y
=x
1
1
+ -y
+
y >3
2
2
< 1 ¢:::} XJ12 < 4
0.25
~
~XY'l
4
.. -"4.
0.5