1971-11-02 — Page 21

華僑日報 All

育教僑 頁一第張六第

1972罡文中學會考試題預習專澜∗文♂은 처형을

數學科

BATANEIL WAH KIU YAT PO

泊僑 TY HALL

IS

sine 1

dose)

and denomi- naton by co se.

二期星日二月一十年一七九一曆公年十六國民華中

1972

(-)

isine

Co se

cose

中文中學會考試題預習專利

世界歷史科

·歐陽鋊豪:

世界不史科預習录及答匀,首术(十一)第二日,明(1972)年至北润,仍些展第二道 沒判出。裝1972年香港中文中學會考騙啡,本科會考範细说,对生,五金

denominator by cose

1994.

MATHEMATICS (1)】

This course provides the candidates of

H.K.C.E.E. 1972 a general revision on mathematics (Syllabus A) and it begins with trigonometry.

Consider a

where angled

triangle ABC.

90 and let / ABC = 6. the following ratios:

AC

Then we

side

sin e

hypotenuse

cos e

adjacent side

BC

hypotenuse

AB

tán G

Opposite side

adjacent side

adjacent side

opposite side

sec =

hypotenuse adjacent side.

AB

BC

hypotenuse

Cosec = Opposite side

It should be noted that: I

(1) The abové trigonometrical ratios of an

angle are numerical quantities.

(11) The sine and cosine of an angle can

never be greater than unity; the secant and cosecant of an angle can never be less than unity, while the tangent and cotangent are unlimited between any values.

cos e

cose

Multiplying both the numerator and

cose (1 + sine) = (1 - sine)

cose (sine + cose - 1·

cose (1 + sine) (1+sine)(1-sine)

cosỹ (sinë + cose –

(1+sine) (cose+s

cosə ('sine + cas

1 + sine

Co se

R.H.S.I

Trigonomettic ratios of the angles

60°

90

30

The most importa nt trigonometric ratios are sine cosine and tangents since the remaining three can be obtained from them taking the correspording reciprocals. (1) The angle o

Consider AFOR right angled at Rand / PQR

ewhere e is small.

As 9 tends to 0, Pand' R tend to coincide i.e. PR tends to zero,hand length of FO approaches. Than of OR.

FR

tane

sino

tano

申明:透保(17931941)

ANG: TENDUME ONRY HOURS

ZH:

ATED: 1917-191524 NOT Year

ANTHERA (17834-1942.

BI 17831011-) :-

17891939) kal

A1789 18OZE WZNANZASA PART) ·

BŹNATES THE D

C1848-1941 (1284)

(3) $1504)

乙:

TRANZEICHEN

·共佔40分,考生必須心。

詳細問15屆(甲、乙、丙护然签者方裂,比間佔60分。

世界歷史科預習題目:

503641783-1911).

SPAR

1 TREA

2.1600(明态網28)中,美國補機(C)末力易。海中的香来写之英國人(

3. HARD, UTAE SETS (7)

A

LORD NAPIER (G) LEE, UCUZAB,

CBX

CF)

002 GO

sin o

cosec

tan e

cos e =

sin 9. cos e

sea

Again, let us refer to the above Fythagoras' theorem, we have

CB2

AC

Dividing throughout by AB

Langle,

= 1 1.6. (B) + (AC)2 =

(2) The angles 30° and 60°

Consider the equilaterál triangle POR of side "a' and draw PM perpendicular to QR.

From geometry we claim that M-is the mid-point of

QR and PM bisects OPR

/ QPM = / RPM = 30°

By Pythagoras' theor

=PM OM?

PM

(a)?

Co

Dividing (1) throughout by

tan 0+1=sec

cos e

COS.

Dividing (1) throughout by sin

sine

COS

sine

Now consider

sin6o

POM

co 360°

Jie 1st cote = cosec

Example (1)

Given see 0 =

tan6o

Find the remaining

sin30°

COM

trigonometrical ratios in terms

Solution: By Pythagorus theorem,

cos30°

(m2

(2m)

we have

外事

WALEEYYA) ROBERT MORRISON (B)H.

IS MATTEO RICCI (C) TILINON (DY NICOLAUS LONGOBAR

DI

D.

3. -

E LORD MACARTNEY (D)

MALORD AMHERST (B) BUE GEORG CHARLES ELLIOT (D) LORD NA

JAMES LEGGE

JUCHITARR : (A) WASIO.B. ROHINSON CRY

C JON POVRING (D) HENRY FOTTINGER

STRANXARXARO TALES MANIA -

All the above results are summarized by: the following table.

Anyle

Sine

Cosine.

tangent

Example (3).

Find the value

olution.

sec45

30

459

GO

LIN HIG

નાના ન

احب ايه

√3

cos 309

sin 600

cos30 = √3

sin60o

=

P:

ö

the above expressio

4 (4) a - 4 (√2)2 - ¦ (£) 2

adjacent:

cose

hypot

sine

tenuse

opposite side hypotenuse.

[cosece

tane

sin e

Opposite side adjacent si

2m

xample (2)

that

tane. + sece. Tane

sece

2m

sine

can30° - OM

(3) The angle! 45.

Consider the isosceles

triangle POR Vith

"PRO-900 and PR

____POR = / QPR =

PR

foras! theorem

RO

PQWZ

하하

tan45)

The angle 90-

- Consider the triangle

POR right angled at R

and £ POR = 90 where

e is small.

As

approaches zero,

QPR approaches 900

and length of PQ

approaches that of OR while PR approaches,

zerok

tane

se ine

sinoPR =

sing0° = =

Cose

PR

cos OPR

sine

CO'Se

1) co se

(Multiplying

Co se

Co se

Co

both the

umerator

tanQPR => OR

tangos

لم

Exerci

(1) Suppose

value of Lan

(2) Given

2mn

Find the

prove that

CO.SA

(ANES

sina:

sinB

(3) Suppose sine - msing and cose - ncos *

find the values of tane and tanx în term of m and n.

(4) Prove the following identities:

costand sind.

cosec.x - iseca

seca coseco-

sin+cot cosa

tan &

sind+ 2sino có sở

+ COS2+ cos

Cosecα

sin

sin

coseca + cot∞

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