1968-12-05 — Page 23

華僑日報 All

Commutative & Associa

Complement Law

identity Law

尙教僑華 真三第張六第

日六十月十年申戊

WAH KIU YAT PO

日僑華 四期星

日五月二十年八六九一曆公年七十五國民華中

一九六九市中文中学試題預語

1969

會考試題預習

數學科

(F) ·喬仲强·

現代數學科(五)

MODERN MATHEMATICS; (5):

第四次預習題解答

(1)設

•2x-3=0的两根,求下式之值:

(b)(2+ £)(p+2), (c)

(d)

(1) Proof of AUB » BUATI

由根與係數之關係。

BU

(k) (~~~1)(p+ £) = ±2++, "A+! Cat!)

= (<+ 6}~2« §a—[(«+p)-2«p]~200

(-3)2 - 100-1882.

= (x+8)2 = 4x8 = 22 - 4 (-3) — 16

5164(因較大,故被取正號)

<+ «p+ p3) = (<~p} [(x+8)_dp]

· [2-(-3)] = 4 × 7=28.

=-10, (a+1)(p+ d) = ~,

82

(2)飯/_p為5x+2元~4=0的两根,求作方程式使其

## $ $ (a) 2×+ß 2ßtd *}} iz−) (a) 1}} <+8=-—,

(b) (2+1), (b+1).

ap=-=

*****484v = (2×+5)+(36-

)=3(+8)=3(-3)

**** =(2++B)(28 + x)=2a+5+B+28

(∞+p) +αß=2(-3) + (-9) = ·

*****1* 3 y ( 3

By 254+

(書) 平成方程式の根和(は

#4 (4+1)(+1) = 1, 18 = 1+ (70)

· = 4+ [=0 Bp 4y2=10y+1=0.

(Hik=)(a) 4 = 2d)

= y+3 › ‹ Bp x=y+z+4>]1⁄2?$${

5(y+ — }) + 2(y + z ) − 4 -

5ly + y + — ) + 2y + — — 4 = 0

5y+4y+#+2y+/-

by + by

+1.

5(y-1)*+ 2(74)-

5+2(Y - 1)—4(y-

10y=12=0

+zy-2-4y2+8y-4=0 Bp 44 -10y

:(a) 25y +304-12=0; (b) 44*_104+1 = (註)本題(解=),稱為方程式之变换(Transformami

tion of Equation)

(3) 38 x-(x-2)x−(m+3)==0 74% £=9+8 ¥**£

25 求m值,並解方程式以核验之

(46) b h i k £ 138] 15, 19 x+ =m-2 <ß=-(m+3)

' = (a+p)=2&p= (m−2) + 2(m+3}

・種類筒

分解

1025

(m~5) (m+3)

(若税=5代入原方程式・得 コピー3x-8-0

3)± (-3)=4×18-3)

(ش)

६६६ &EE

AMMMC

Since the membership table of "AUB and Bua aze identical, they are equal

(2) Proof of (AUB)UC - AU(BUC)

(AUB) U C

MM!

MAT MAT MAT

AU (BUG)

Since the membership table of (AUB)UC and) AU(BUC) are identical, they are equal,

(3) Proof of “nu » A and ano

६६६

Bence. Ang Awand And

(4) Proot orfan

40 A

Hence AD ATTA

Worked examPLAU

4) Examples of simplications

1. Simplify (AOB'NC® JUI ANBING ND} {ADO" } L.H.S.- ((ARÁNC®)u(AMB®NG' WD)JU (ANC

Simplify

..... Associative Law

Absorption Law

-XLANO`JU ((ANC) B.)

Commutativa d Associative Lawa) Absorption Law

(XUYUZ')N(X'NI '72); H.S.-((XYZ}}^{(XUY)^2}

Law

Associative & De

•* ́ ̄ {( XUY ] 11 2] 1 {{ XUY ]u z }\

Commutative Law

Distributive Law

-3x-3-3(X+X+

2m +10

分解

(x+3)=0

x= - 3 (重根)

2E0

卡(重根)

(6) at?

(8) Examples of proving identities

Prove that LAUK'UC! } {} %17 ( BNC ) { ► Proof

(AU{BAC)"}NŢAU(BIC)].

De Morgan's law.

AU{{BMC) N(BAC)}

AUD

Distributive Law

Complement Law aldantity Law

2.[Prova"that [ M(A •UB]]U{ BO{ A 3U B' )

Prapf

AM(AUB)|U BR( A ?U B` }}

( An A *- Ju ( An B ) ]u {{BA® )U{ BI B' }}

(dol AAB)(U

Distributive Law.

Identity. Law

(BIA)U (B. Complement Law

BOLAVA BA

Commutative Law Distributive Law Complement Law Identity Low

(C) Examples involving subsets

Prove that if AB and A<C. then As(BAC). Proof

Assume X-FA Then -x-9 ATEGO XEC 10. BDC

Therefore,

АС ВЛС

that AcB 1f B'CA

AP6umption A B W. Acc.

Defination For intersection of 2 sets

Definition or a

subset of a given sev.]

The statment means that (1) if ACB then

BLA'

and (11) if BCA

Proof of (1) i

Assume bi B

Then biß:

Since DEB, A Since bEA. BE A '>

then ACB.

Assumption Def. of the complement of s

Ac By

*. Def. or nes complement of a set

Therefore, firibɩ B', bɛG! Hence BZAZ

Proor of (11)

Assume 4 BLA Then

Def. or a SUDDER of a given set

Assumption Def, of the complement of a set

BCA

Then

a

a B

If at B a B

Why

Therefore A<B

Work for the week!

(1) Simplify (ANB)U CAN BOC "

Def or a subset ofa:g)

(2) Simplify :((Xu?}{(x*UT ® )]u(xny).

[1]{Prove that{{A!UB! }n{A'u_B}^\ {ÂU B }} ~ŢA \\ B_

(4) Prove that¦{ANBAC)U{A'NC)U(BSC)]={0}

(5) Prove that if¡A=8.Ethen]BA

(a-b), (b+c), (c-a) M 75 hk

b-c-ok cato

(畢)

Lori) 14

(1) AB CD 11

=4(9+6541+41+9¬614+41)=25(id2)

2x1.

8p" d= = (3+14),

B==(3-547)

**¥**<=4(3+140)+4(3-(41)

*x19 x-(-3−2)x−(−3+3)=0

Ep x+5

根平和

(4) % m. n bjjuR.

比两根亦為有理數

2+(-5)2 = 25 (142).

JE 3mx-(2x+3x)x+2n=0

(3z i4 −) * * *171 £ A=[ (am+3x)] −4x3m=2?

4m+12mn49n-a4mx.

== 4 m2-12mn+In

故其根笃有理數

(am-3n)" %-2278★

Q:E.D.

($£14➡) /1⁄2 *$** † 3mx-2mL−3RX+21=

MI(3x-2)-2(3x-2)=0

(3x-2)(mx-n)—6

善或發,其根為有理數(紅)

(5) || 2x-3x-3+k{x2+x+2)=02@ +8 +84 at

并核驗之

(解上因两根相等,其判别式△口原方程式可化骂

化簡

(k+2)x+(R−3)x+(2k-3)=0

Am (k-3)=4(k+z)(zk−3)—o

1分解

1-6k+9-8k -4k+24=0

7k+10k-33=0

(k+3)(7π-11)=0 [k=-34/

(86 Tju) k=-3.04, 1»J£÷ ÁÀ

#m z 11.

(解)原方程式分母

----- =1,两根同值而異號,試

a(x+b»m) + f (x+a+m]=(x+Q=m) (x+b_m)

2x+a[f=m}+bx+bla-m

-11-1

• X2+(4¬m+b=m}X

+(a=m) (b-m)

X-2mX+ (a+m}{f^m)—a{b_m)− f(a-m)=0. 誠又為其一根到,亦為其根由根與係數飔係

答:

(7)設 a& c均笃实數,方程式

(x-f)(x−c)+(x−c)(x−q)+(x~a}(x-4) = 0 = @ #B +

it amb C

【正)原方程式去括号

x2−(b+c)x+b¢+x=(c+a}x+ca+x^(a+b}x+ab=

10 3x*~2(a+b+c)x+( &c+ca+ab) = 0

因两根相等,故判别式為零

A=[2(a+b+c)] -4x3(berca+ab)=0}

4(a+b+c)2 = 12 (bc+ca+ab)=0

(a+b+c)~36bc+ca+ab)==0

a2+of+c2-abibc-ca=o

20+2b+26'-zab-abc-zca—0

(a−2ab+b') + (b=zbc+c)+(c2—zca+ a®)—

(a−b)2+(b−c)2+(¢

*#*#34 MB,(Intersection of

PAB1 - 43 14-0 典AB相切P桌且典CD相切,

(分析)設日為訴求园之园心,則QP為半程,故QP1AB所以 祇是典AB切柊ㄗ奌园心(略法與CD相切之另一搏)是 無限多的,其軌跡是過P奌而與AB要直之直线,只祇典AB, CD相切(略切奌善P),則Q奌典ABCD等距離,故軌跡 為其交角之平分线,作出此两軌跡之直线,其支奌Q即為好

(8 km) AB CD# ok

PABATI.

求作一团Q使與

AB W☀?), 1 cotto

(142) 1.442807

R4B0C M4A #lel

||2.LE PAT ABWE

Kathuk

5. viata c. Qṛb

半程作园,

4 Ul Q & Q wc, QP 3 $48442, 8];Q; Qmańžnk.

PROD ME

(4)求作一园,切一已知因於性設奌,且典-已知直线相切协

(**:*8*8 +0 4 * to atom (4)

(2)袁作一园,tan已知直线於定奌,且與一已知园相切 (3)求作一团,切一已知园於在設桌,且澳另一己知园相 (4) 0, PAB) 1 KAB TEAM-10 POBA*ck

TØRKDAS CA=2AD

(5) A30BD - 2* & DB A 13-1 BC M◊ BA¬ZAC

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