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Rèn luyện kỹ năng giải hệ phương trình cho học sinh khá giỏi trung học phổ thông

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



 





             


23
23
25
28
31

31
32
33
36
36
39

42
45
45
49
57

69

69
70
76

79

85
86
7


10,10 
nm
aathìnma

2.7.3. 
2.8. .
 





O 

87
88
89
95
99

99
99
114
116
117
118

















8

1.  
, 
 “Giúp học sinh phát triển toàn diện về đạo đức, trí tuệ, thể chất, thẩm mĩ
và các kĩ năng cơ bản nhằm hình thành nhân cách con người Việt Nam Xã
hội chủ nghĩa, xây dựng tư cách và trách nhiệm cộng đồng, chuẩn bị cho học

sinh tiếp tục học lên hoặc đi vào cuộc sống lao động, tham gia xây dựng và
bảo vệ tổ quốc”
 “phát huy tính tích cực, tự giác, chủ động, sáng tạo của học sinh,
phù hợp với đặc điểm của từng lớp học, môn học; bồi dưỡng phương pháp tự
học, rèn luyện kĩ năng vận dụng kiến thức vào thực tiễn; tác động đến tình
cảm, đem lại niềm vui, hứng thú học tập cho học sinh”.
Trong 
p, cung ,




. 

, , . 


tr logarit. 
. 


. 
 c
9
 ,, 
 


.
2. 

 
trong
 - 

  - 
th -
- 
 -
 
, 
.
3. 
- 

- 
+ 
+ 
+  

4. 
-  
.
10
-          
.
5. 
 10A11 n2010-2011 

6. 


+ 
7. 

m, , 
                
, .
8. 
     N         

+ 



9. 
            

;
;
.



11
:  
1.1. K 
1.1.1. , 
         

kĩ năng là năng lực sử dụng các
dữ kiện, các tri thức hay các khái niệm đã có, năng lực vận dụng chúng để

phát hiện những thuộc tính bản chất của các sự vật và giải quyết thành công
nhiệm vụ lí luận hay thực hành xác định”.
Theo [13] “Kĩ năng là khả năng vận dụng tri thức khoa học vào thực
tiễn” 

Theo [8] “Kĩ năng là một nghệ thuật, là khả năng vận dụng những hiểu
biết có được ở bạn để đạt được mục đích của mình, kĩ năng còn có thể đặc
trưng như toàn bộ các thói quen nhất định, kĩ năng là khả năng làm việc có
phương pháp”.
Theo [7] “Trong toán học kĩ năng là khả năng giải các bài toán, thực
hiện các chứng minh cũng như phân tích có phê phán các lời giải và chứng
minh nhận được”.
  
  


1.1.2. 
 

   

.
12






g 

, 
,  hai 

- Tr


 


- 





 
- 

- 

- 

13

              



- 
 

.
- e


- 
1.1.3. 

-  
.
-  
- 
- 
- y

1.1.4. 
c c 
- 
 

- H

14
- d, s

1.2. y
1.2.1. 
:
“Mục tiêu giáo dục phổ thông là giúp học sinh phát triển toàn diện về
đạo đức, trí tuệ, thể chất, thẩm mĩ và các kĩ năng cơ bản, phát triển năng lực
cá nhân, tinh năng động và sáng tạo, hình thành nhân cách con người Việt

Nam XHCN, xây dựng tư cách và trách nhiệm công dân; chuẩn bị cho học sinh
tiếp tục học lên hoặc đi vào cuộc sống lao động, tham gia xây dựng và bảo vệ
Tổ quốc” (Theo2005)).
:
- 

- P
- 
;
- ;
- , 
.

. T 
.
1.2.2.   THPT
 
- 

- 
+ 
15
+ 
+  , 
+ .
1.
Theo (2006), p, 


   ,        

 
             
 
t

 







:
- : P;
- ;
-;
-;
-;
-.
16


.
1.5. 

:
1.5.1. 
 sinh trong 
  


, 
.

:
-
.
- .
-: G k

c
.
-

.
:
-
.
-
.
17
-m
.
-
.
1.5.2. 

.
1:
- 

.
- .
- .
2:
-              



- .
- .
3:
              
.
4:
- .
- .
1.5.3.   
 q
 
18







1.6. 
   quan




 

              

.








19



     
 
           



,
             




 
 sinh.
2.1. 
2.1.1. 


. K
, 
. 






)2(.2
)1(123
22
yx
yx



2
13 

x
y

20
















.
13
7
1
076132
2
13
2
2
2
x
x
xx
x
x



11  yx
.

13
17
13
7
 yx
.
 :
 







13
17
;
13
7
,1;1
.
 :  
 khi  
 


 
1)





;9324
352
22
yxyx
yx
2)





;0153
692
2
yxx
yx

3)






.4432
12
223
yxyxx
yx

: 1)
 
1;1 
2)
 
2;3
3)
 
1;1
.
2.1.2. 
2.1.2.1. Định nghĩa
      I          

2.1.2.2. Ví dụ






.2
42

22
yx
xyyx


I 

21
 





., xyPyxS 

PS 4
2

.













SP
SS
PS
PS
42
06
22
42
2
2







































.
2
7
3
1
2
2
4
3
2

P
S
P
S
S
P
S
S






1
2
P
S
( )







2
7
3
P

S
()

yx
xy
yx
P
S
,
1
2
1
2












:







1
1
1012
2
y
x
XXX
.
  
 
1;1
.
2.1.2.3. Phương pháp giải

- 
yxPyxS ., 
, 
PS 4
2

.
- S, P. S, P

PS 4
2

.
- x, y: x, y 

0
2
 PSXX
.
: Ta c
SPSyxPSyxPyxSyx 3,2.,
333222

.
2.1.2.4. Lưu ý






.3
1
22
xyyx
yxyx

I.
22
t=-y 






3
1
22
txtx
ttxx

I 
 (1; 1).
x-y x.y 
yt 
I.

 
 
.3).(,2)(
2
33222
xyyxyxyxxyyxyx 


 





;2
3
)1
22

xyyx
xyyx








;1
1
)2
22
33
yx
yx






;13)(2
2
)3
2222
xyyx
yxyx







;8
22
)4
33
yx
xyyx






.28)(3
112
)5
22
yxyx
xyyx

1)  (1; 1).
2)  (1; 0) ,(0;1).
3) 
4)  (0; 2), (2; 0).
5)  (2; 3), (3;2), (-3;-7), (-7;-3).











;2
4
)1
22
x
y
y
x
x
y
y
x
yx









;12)(2
3
)2
22
22
yxxyyx
xyyx






;6
1
)3
22
xyyx
yxyx






;1
2
)4
22
yxxy

yxyx






;2)1()1(
4
)5
22
yyyxx
yxyx








.)(7
)(19
)6
22
222
yxyxyx
yxyxyx

:

1) - 





0
0
y
x

- 
, yxPyxS 

PS 4
2


23
- 


















PSPS
PSPS
PPSS
P
PS
S
23
6
2)3(
4
2
3
2
2
2

              

023
2
 SS
.
    



















10
55
;
10
55
,
10
55
;
10
55
),1;1(

.
2) x+y=S, x.y = P. 
PS 4
2

.






)2(122.
)1(33
2
SPS
PS


1
3
2

S
P


230363
3
 PSSS


-1;-2), (-2;-1).
3) ba  : (-1;1), (-1;-4), (4;1).
4) hai : (-1;0), (0;1).
5) y = a
H













2
4
2)1()1(
4
22
22
22
axaxax
axax
aaaxx
axax


.
hai : (1;2), (-2;-1).
6) y = a
H







)(7
)(19
22
222
axaaxx
axaaxx

.
ba (0;0), (3;2), (-2;-3).
2.1.3. 
2.1.3.1. Định nghĩa

.
24
2.1.3.2. Ví dụ
 








.232
232
22
22
xyy
yxx
(QG2000).

Tr

0)()(3)(2
222222
 yxyxxyyxyx







.1
0)1)((
yx
yx
yxyx



)(
232
22
I
yxx
yx







)(
.232
1
22
II
yxx
yx













1
1
y
x






.2
2
y
x

.
 hhai : (1;1), (2;2).
2.1.3.3. Phương pháp giải

- 








0),(
0),()(
yxf
yx
yxfyx

- 

 :







;21
21
)1
3
3
xy
yx









;2
2
)2
xy
yx








;312
312
)3
xy
yx











;
3
2
3
2
)4
2
2
y
xy
x
yx










;43
43
)5
y
x
xy
x
y

yx












.
1
2
1
2
)6
2
2
x
x
y
y
y
x

:
25

1)  ba 


















2
51
;
2
51
,
2
51
;
2
51

),1;1(
.
2(4; 4).
3 























.2
11
1

0
0
11
1
2)(
11
)(211)(2
yx
yx
yx
yx
yx
yx
yxyxyx

.
+
2
1
11  yx


yxyxyxyx 
4
11
4
11
611)(2



541231
4
11
2 






 yyyy

























8
511
8
511
8
511
8
511
0294416
4
5
2
xy
xy
yy
y





















8
511
;
8
511
,
8
511
;
8
511
),1;1(
.
4) (1; 1).
5) 








xxyy
yxyx
43
43
2
2

(-2; -2).
6) 







xyxy
yxyx
2
2
2
2

ba 
)3;3(),3;3(),0;0( 
.


26









;
31
2
31
2
)1
yx
y
xy
x













;
2
3
2
3
)2
2
2
2
2
y
x
x
x
y
y








;4432
4432
)3
xy

yx










.
4
1
1
4
1
1
)4
2
2
xy
yx

:









xyyxy
xyxyx
32
32
2
2


)2;2(),2;2(),1;1(),1;1( 
.
2) : (1; 1).
3) 
  (3;3).
4) 









2
31
,
2

31
.
2.1.4. 
2.1.4.1. Định nghĩa
:








)2(.
)1(
2
2
22
2
2
1
2
11
2
1
dycxybxa
dycxybxa

2.1.4.2. Phương pháp giải



 
1
, d
2


)3(0
22
 CyBxyAx
.
 - 
- 



).4(00)()3(
222
 CBtAtyCBtAt



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