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H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

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Page 1: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

48

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

Page 2: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

49

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

2( )f x ax bx c= + +

0a ¹a

( )

( )( )

2 2

2

2 2

2 2

1( ) 4 4 4

4

12 2 (2 ) 4

4

1(2 ) 4

4

1(2 ) ( 4 )

4

f x a x bax aca

ax b ax aca

ax b b aca

ax b b aca

= + +

= + +

é ù= + - +ë û

é ù= + - -ë û

2 4b ac= -2b2 4= bb

21( ) (2 )

4 4f x ax b

a a= + -

0a >( )f x2 0ax b+ =2

2

bx

a= -x

4a--

,2 4

b

a a

æ ö- -ç ÷è ø

ö÷ööæ

çææ

èçç

0a <( )f x2 0ax b+ =2

2

bx

a= -

4a--,

2 4

b

a a

æ ö- -ç ÷è ø

ö÷ööæ

çææ

èçç

,2 4

b

a a

æ ö- -ç ÷è ø

ö÷ööæ

çææ

èçç

).هو مشتقة الدالة( لاحظ أن

Page 3: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

50

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

2 2( , )f x y ax bxy cy dx ey k= + + + + +f

0a¹0b¹0c¹c0b¹b

2 2 2

2 2 2 2

2 2

1( , ) (4 4 4 )

4

1(2 ) 4

4

1(2 ) 4 4

4

f x y a x abxy acy dx ey ka

ax by b y acy dx ey ka

ax by adx aey y ka

= + + + + +

é ù= + - + + + +ë û

é ù= + + + - +ë û kù2 22 2

ûyyyyyy2 2yyy2 22 2

II0¹0¹

2 2

2 2 2

22 2

22 2 2

1( , ) (2 ) 2 (2 ) (4 2 )

4

1(2 ) (4 2 )

4

1 2(2 ) 2

4

1 2 2(2 ) ( ) ( )

4 4

f x y ax by d ax by ae bd y y ka

ax by d d ae bd y y ka

ae bd dax by d y y k

a

ae bd ae bd dax by d y k

a a

é ù= + + + + - - +ë û

é ù= + + - + - - +ë û

é ùæ ö-æ ö= + + - - + +ê úç ÷ç ÷è øè øë û

é ù- -= + + - - - + +ê ú

ë û

kù2 22 2

ûyyyyyy2 2yyyy2 22 2

kù2 2 22 2 2

ûyyyyyy2 2 2yyy2 2 22 2 2

2 22 22 22 22 22 22 22 22 22 22 22 22 22 22 2 222 22 2 22 22 22 22 22 22 22 22 22 22 22 2 222 22 22 2

èçç yyyy

èçç kyyyy

ûúúø÷÷y

ø÷÷

2 2 22 2 22 2 22 2 2é 22 2 22 2 22 2 2222 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 2((((2 2 22 2 22 2 22 2 2 k) ( )) ( )) ()ûúú) ( )

0

2ae bdy

-=

2 22 2

0

1 (2 )( , ) (2 ) ( )

4 4 4 4

ae bd df x y ax by d y y k

a a a a

-= + + - - + - +2 22 22 22 2( )( )( )0

2 22 22 2

44a a4

yyyxaac

ddee0c¹c

2 22 2

0

1 (2 )( , ) (2 ) ( )

4 4 4 4

cd be ef x y cy bx e x x k

c c c c

-= + + - - + - +2 22 22 22 22 2( )( )( )0

2 22 22 2

44c c4

0

2cd bex

-=x2 4b ac= -2b a2 4= bb

حيث أن

Page 4: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

51

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

0

2

2

2

d b

e cx

a b

b c

-

-=x0

2

2

2

a d

b ey

a b

b c

-

-=

0 0( , )x y

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

2 2

0 0

(2 )( , )

4 4

ae bd df x y k

a a

-= - +

44a a4

2 2

0 0

(2 )( , )

4 4

cd be ef x y k

c c

-= - +

44c c4

2 2

0 0 0

1( , ) (2 ) ( ) ( , )

4 4f x y ax by d y y f x y

a a= + + - - +2 22 22 22 2( )( )( )2 22 22 2

0 0 00 0 0

2 2

0 0 0

1( , ) (2 ) ( ) ( , )

4 4f x y cy bx e x x f x y

c c= + + - - +2 22 22 2( )2 22 22 2

0 0 00 0 0

0 0( , )x y(

2 0

2 0

ax by d

cy bx e

+ + =ìí

+ + =î

2 2 2 2

0 0 0 0

1 1( , ) (2 ) ( ) (2 ) ( ) ( , )

8 8f x y ax by d y y cy bx e x x f x y

a cé ù é ù= + + - - + + + - - +ë û ë û0 0 0 0

1)0f0 0 00 0 0((0 0 00 0 00 0 0

c8é ù2 2 2 22 2 2112 2 22 2 22 2 22 2 2 22 2 22 2 22 2 22 2 22 2 22 2 2 22 2 22 2 22 2 22 2 22 2 22 2 22 2 2

0 0 00 0 0ë û0 0 00 0 088

0 0 00 0 00 0 00 0 00 0 00 0 0(( 0 0 00 0 00 0 00 0 00 0 00 0 00 0 0(( 0 0 00 0 00 0 00 0 0c88

(( 0 0 00 0 00 0 00 0 00 0 00 0 0

2 2 2 22 2 22 2 22 2 22 2 22 2 2( ) (2 ) ( )( ) (2 ) ( )( ) (2 ) ( )( ) (2 ) ( )( ) (2 ) ( )( ) (2 ) ( )2 2 2 22 2 22 2 22 2 22 2 22 2 2

0 0 00 0 00 0 00 0 00 0 00 0 0

Page 5: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

52

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pbIII0D =

2

2

2 2

22

1( , ) (2 ) 4 4

4

1(2 ) 2 (2 ) 2 4

4

1(2 ) 2(2 )

4

1 1(2 ) (2 )

4 2 4

f x y ax by adx aey ka

ax by d ax by bdy aey ka

ax by d d ae bd y ka

dax by d ae bd y k

a a a

é ù= + + + +ë û

é ù= + + + - + +ë û

é ù= + + - + - +ë û

= + + + - + -

( , )f x yf

2 2

0 0 0

1( , ) (2 ) ( ) ( , )

4 4f x y ax by d y y f x y

a a

D= + + - - +

0<0<0a>a0 0( , ) ( , )f x y f x y³f( , )x y(

0 0( , )x y

0D <D0a<a0 0( , ) ( , )f x y f x y£

0 0( , )x y

0D>D0a>

( , )x y(2 0ax by d+ + =

2

0 0 0( , ) ( ) ( , )4

f x y y y f x ya

D=- - +f-¥-y¥

2

0 0 0 0

1( , ) (2 ) ( , )

4f x y ax by d f x y

a= + + +f¥¥x¥

0D>D0a<a

Page 6: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

53

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

IIII0D=

2 0ae bd- =22

221

( , ) (2 )4 4

df x y ax by d k

a a= + + + -

0a>a

2 0ax by d+ + =2

4

dk

a-k

0a<

2 0ax by d+ + =2

4

dk

a-k

0D=D2 0ae bd- =2

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

2 0ax by d+ + =2

0=0=2 0ae bd- ¹

221 1

( , ) (2 ) (2 )4 2 4

df x y ax by d ae bd y k

a a a= + + + - + -

1 1( , )x y1 12ax by d h+ + =

22

1 1 1

1 1( , ) (2 )

4 2 4

df x y h ae bd y k

a a a= + - + -

:للهيئة أن هو الشرط معنى

.متناقضتان لمعادلتانا: القول يكافئ وهو .لا يوجد حل

Page 7: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

54

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb 2ax by d h+ + =

1 1( , )x y(

( ', ')f x yf( '', '')f x y

1 1( , )f x yf1 1( , )f x y

1 1( , )f x yf

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

( , )f x yfyx

( , )f x yf

( , )f x yfyy

Page 8: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

55

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb2 2( , ) 4 7 5 4 12f x y x xy y x y= + + - +

27 4 4 5 31 0D = - × × = - <D4 0a = >a

8 7 4 0

7 10 12 0

x y

x y

+ - =ìí

+ + =î

0 0( , ) (4, 4)x y = -

min (4, 4) 32f f= - = -

2 2

2 2 2

2 2

2 2

2 2

2

1( , ) (16 28 20 ) 4 12

4

1 7 7(4 ) ( ) 20 4 12

4 2 2

1 7 31(4 ) 4 12

4 2 4

1 7 31(4 ) 16 48

4 2 16

1 7 7 31(4 ) 4(4 ) 62

4 2 2 16

1 7 7(4 ) 4(4 )

4 2 2

f x y x xy y x y

x y y y x y

x y y x y

x y x y y

x y x y y y

x y x y

= + + - +

é ù= + - + - +ê úë û

é ù= + + - +ê úë û

é ù= + - + +ê úë û

é ù= + - + + +ê úë û

é ù= + - +ê úë û2

2 2

2 2

2 2

31 31

16 2

1 7 31(4 2) 4 ( 8 )

4 2 16

1 7 31(4 2) ( 4) 31 14 2 16

1 31(8 7 4) ( 4) 32

16 16

y y

x y y y

x y y

x y y

+ +

é ù= + - - + +ê úë û

= + - + + - -

= + - + + -

0 4y = - 0 4x =x

Page 9: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

56

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

2 2( , ) 6 9 8 12f x y x xy y x y= + + - -

26 4 1 0 0D = - × × =

2 2 1 ( 12) 6 ( 8) 24 0ae bd- = × × - - × - = ¹

2

2

2

( , ) ( 3 ) 8( 3 ) 12

( 3 4) 12 16

(4 3 , ) 0 12 16

f x y x y x y y

x y y

f y y y

= + - + +

= + - + -

- = + -

yy¥¥¥

y-¥-¥-

1 1( , )x y1 13 4x y h+ - =

2 2( , )x y3 3( , )x y1 1( , )x y1 1( , )x y(

2 2 2( , ) 12 16f x y y= -f3 3 3( , ) 12 16f x y y= -

2 1 3y y y> >y2 2 1 1 3 3( , ) ( , ) ( , )f x y f x y f x y> >

1 1( , )x y

Page 10: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

57

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

2 2( , )f x y ax bxy cy dx ey k= + + + + +

2 4b acD = -D

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

0D <0a <0 0( , )x y(

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

0D <D0a >0 0( , )x y(

2 0

2 0

ax by d

bx cy e

+ + =ìí

+ + =î

0D >D

0D =2 0ae bd- ¹2

0D =2 0ae bd- =20a <

2 0ax by d+ + =22

4

dk

a-k

0a >2 0ax by d+ + =2

2

4

dk

a-k

Page 11: H Âflbr€a@ÖÜ»€a I öflΧلقيمة_العظمى...50 @pb HÂflbr€a@ÖÜ»€aI öflÎ f xy ax bxy cy dx ey kf(, )= + + + + +2 2 b„0 c„0 b„0 a„0 2 2 2 2 2 2

58

öflÎI�������Âflbr€a@ÖÜ»€a����������H@pb

2 2( , )f x y ax cy dx ey k= + + + +

ü ,2 2

d e

a c

æ ö- -ç ÷è ø

ü ,2 2

d e

a c

æ ö- -ç ÷è ø

æçææ

èçç

ü

ü