1986-07-04 — Page 34

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頁二第張九第 日八廿月五年寅丙磨夏 WAH KIU YAT PO

報日僑華

>3.

Ans.

1986

When x 0, (x−3)(x+1)·

<0, -1<x<3,

{n}f(x)=x3+bx*skx+2

(c)

五期星

附加數學建議答案

日四月七年六八九一层公年五十七國民中育教僑華

中學會考試題預習專欄

Sam of rest

附加數學建議答案

Suggested Solution to

Additional Mathematics

IT 1986

Since C is the mid-

sinsdy

point of AB, vhere:

1. P.

*2-3*

When n

{n+1}

* are the x-co- ords, of A and B.

Saggen LeA

Additional

T. 1986

1. Let re

-(2)-(1):

Ay=x+3x Ax+3x(6x)

AX

+ (b =)3

Ax¬u(1x)-3x2

loga+(x+1)logb=0

(Inga) (logb)x+logb

0

For equal roots,

(logb)2-4(logn)(logb)

Togb-41oga=0

logbaloga

For turning points',

drg 2

3x^42hx+k=0

As the turning points

are distinct,

(4b)2=4(3)(k)>0

i.e. 3k..

Now, y-2;

2=x+hx

+hx+k=0 |

As the roots are not real,

(#)0C=0A+AG

>8+2b" As AC-20B

"2

=a+b

TOB+100

(a+b)

(b)Given:PR÷Rq=h: (1–h)

h00+(1-h)op

-_-3 ( 2+4b) + (1~})}

→(3a-ha+8hb)

b-a. Ans

(ii)OR-KOC

f(x)=4k+18x-kx“

df ()-18-2kx

́dx.

For stationary

values,

-2kx=0

and

11 1111

Ak <0

h4k

3k < b2 < 4k (b)For (-2, 0),

ADS.

(-2)2+h(-2)2+k(~2)

-8+4h−2k+2=0

k-25-3

From 3k <h2 <4 64-94124

81-12 *.6h-9<12 and b2¿ 8h-12

--6k+970 and1 à -8h+1240

As

Considering sinflar

PM OM

10pine

110gine

210sine

2cose

But-P-PH⋅

-10sine

20cong from (=))· kožne

11.

issuming that P

true for nek,

11.

For nek+1,

1-212-3 *k{k+1} +(k+1}(k+2)

"k+1" (k+1)(k+2)

(k+1)

k+1

dx

For stationary valu ar(x).o

(x+1)(3x+5)=0

20(cos"0-1

(sin942coal)

(sip0+2ca89)– (20ningcost)

(siu@+2cose)

(cos0–2aine):

For stationary points,

· (k+1)+1

.By the principl

mathematical induction, P is

for any positive integer n

For (a+b)", the (r+1)th term

For (42)

the 3rd

tera

ane

(istan38)

=tan 0-1

y- Stap cao-6+C

• f tan^edo-y+0+Cg

where CC

-tan30-tane 494€

Alternativ

ftan ede

Ans.

Stan (sec e-1)de Stan 0 sec ade- Stan ode Stan ed(tans)- {sec^0−1)dg

and

(h-3)2>\0 (h-6)(h−2) <0

*h is any intoger

except 3 and 24k<6;

„b=4 or 5°

Por h=b, k-5,

a@=20sin@cose

Zsing 20sinecose°

Area of aquare

But

d? de

(3k+L)x-(2k−1}y+ +(k−11)=0.........(1) alope-2k-- (887)

For Lx-2y+lim0p.

slope

For m

3k+2

tan45°-1

9k+6««£k+1

The equation of the

(~152)x-(-11-1)+

(7-11)-0 x+3y-18=1)

Ans.

For 7,

3k+2

•3 ⇒ 3k+2=6k-3

2k-1

Atia.

The equation of the second line:

Now,

d2f(x).

ax

}Given: OF AD

màxim when

4k 18()-k()-45

4k‍+162-81-45k

+81-0

k-z or 9

2

#Differentiating the

expression v.zat, zi

-†(8b-a) ́ ́

Ang

(=-1 or

and y=0

Since ų lies on FT

FT UPO Xb~a~ μ•z (8b~g) ~=p • (8)

The equation

tangent in

y-1-(—)(x-2)

5x+4y-14-0

the

X=3(†)(8)

3. (1+j) {(c+4)is(c-4}}}

| 2+2||(c+4)1+(x-4);}

~(√1~+1^) ( ) (c+4)2

√(24) −(√2)(√202+32)

Using cose ab Where O-angle between

and b.

20

240 +16

1-2n

neany integer,

(b)(i)z»r(conûsisine),

Zer(con9-isinė)

(Cosmo+isione)

(COAND—isimmo)

Anx

(a) Iz-21-1

Let z-xsiy

{{(x-2)+iy| −1 (x-2)2+y2-12

(b) {(x−1)+1y] = {(x-3)+iy}{

Putting 2 into

d2t(x)

x+870

when

giving a min. pt.

=6x+8 <'0' when

x=—- giving a max

NO

S-10core

S*20cos0 d5-20(-nine);

at

de

(ii)}

d£. 20sinO.

√2

20√1-c03

(cose+ising)TM

+(coso-isine) ={2, Where G-

20

(10)

√2 using (b) (1) cosae-√2

Tr=1:

5

=-2x=1 by (a)

1 or 8n1 where

is any (+)▼¢

integer

(c)(i)(1+i)P-(1-1-)P-0

(141)-(1-1)P

[+y.

1-(1)

The points of

intersection are:

241 and 2-1. Ans.

paz

vkøren in any (+)ve integer.

(11)(141

(1-1)

NR=5cose h-ON-S-NR

420co80-5cond=15cond

k=5aino

The locús.

1-1

sinecos 0+2cos

42811

̈0 when.

0-51.56

Now,

0-51.56

G

(a)Area A-(y-23)(x-16).

But xy=3600

******=(3600_25)(x−16)

Aw

-3600 16x3600

57600

4000.

-25x4400

(b) d4 −57600(-1)_25

n(n=1)2=40

-n-200 (x+4)(x-5)=0;

ди5 Ans

The coefficient of

Since the roots gre equal,

(-4cose)

4(3)(2sine)

con 8-6ginė×0

(sing+2)(2)

or-2.

(rejected)

0-150 as.0 in ahtuse

Ane.

sin2g+sin4u

20440

Jcos

2sin30cos@=cose

To prove

fof(x)dx= fof(a-x)dx

Let -AA

x--du

1..5,- ) of(x)dx

-- fof(a-u)du

fof{o-x)dx

using (a)

-25x Ans.

Q(2sin30−1)-0 cose-0 or win30-h

20+1

30+n't

(11) 。rsin2xdx

8-3+(-1)", where

Por stationary valuen,

57600-25% -0

When I«AS,

3600 48

(48-16)

1600

Now, 4-(-2)(37690)

dr

40 when x=48.

The largest value of

the area, A=1600

(c)(i)As A decreases

increases, then

(a)Slope of AB

(23+2)x−(20−1)y+

(-11)~0 32-y-4=0

(ii)Since L, is parallel

to (1), 3k42

The line Lis

(-11)-0 x-2y+7=0

- fo(7-x)xîn2(t-x)dx

using: (•)

- J (1-x)sin xda

sinh sinh

Tip

idr.

Ô sin xin gæsin_xdx

Take the point (0, 7)

cance from (0, 2)

0_2(7)

Distance from (0,7)

57600

25 <0.

57600-25x-

x-2304>0

(x−48)(x+48)>0.

x L-48 or ≥ >48

Адв:

* >48 112 ≥50, the largest value of A

57600

4000~~(50)-25(50)

decreasing,

-1598

Ans.

(d) Gives:

3600

1600 €150

5

3600:

Ans.

Aree of A APC

→(Ga−3n+30-6s-10s+9)

(39-138) -(39–138)--13

136-26

138-42

(1-1) ·(1-1)-1

AL

1+i)(1−i)

(1)(1–i from (1)

Алв.

(15,0);

Ris in the 1st quadrant, the locus

ashöv¡!

1600 Cz. É 2025

40 X645

Ans.

When x45, (ver

(48), A 18

increasing.

57600

-1595

The largest value of

25(45)

Wher

>0, (x-3)(x+1)

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三月

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有質關定府日叁在

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九報 力廣龐讀印柯必社必學必家必工

Equation of AB:

y-2-(x-3).

*=siz=3m+2

(x-2)

報日僑

(1-cos2x)dx

-

(x-12x

6-0]

Ans)

(rejected)

10.

x-2y+10~0 ▲as,

(b) At x-axis, y=0,

+(k+11) --11-k

3k+2 3142:

•*. Aren, A-(1)(-)

For

+11)**

• 2(3k+2) (2k−1)

[2(k-11) (3k+2)

(3k+2)" (2k-1)

(2E-1)-

(k-11) (12k+1) (3k+2), (2k−1)

ationary painte,

sinxdx

(*ain(h-x)ax

(-x)+cos(x)

using (a)

sinzuz

Bînx+COST

-(k~11) [12k2+2k-lym 12k +131k+11 -(k−11)(133k+7)=0

kall or t

0

Since x and y-axes are positive,

廣告部電話:

490884

and

sing+cos

When

19 the

is minimum.

And

(c)The required line is

3x=2y+1=0% TÄDA.

全經包專新歷六一 僑濟羅刊聞史月九刊 稱報萬豐翔悠五二在 許導有富貴久日五於

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