22
Teaching & Learning Plans Plan 10: Trigonometric Functions Leaving Certificate Syllabus

Plan 10: Trigonometric Functions - Project Maths

  • Upload
    others

  • View
    3

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Plan 10: Trigonometric Functions - Project Maths

Teaching & Learning PlansPlan 10: Trigonometric Functions

Leaving Certificate Syllabus

Page 2: Plan 10: Trigonometric Functions - Project Maths

The Teaching & Learning Plans are structured as follows:

Aims outline what the lesson, or series of lessons, hopes to achieve.

Prior Knowledge points to relevant knowledge students may already have and also to knowledge which may be necessary in order to support them in accessing this new topic.

Learning Outcomes outline what a student will be able to do, know and understand having completed the topic.

Relationship to Syllabus refers to the relevant section of either the Junior and/or Leaving Certificate Syllabus.

Resources Required lists the resources which will be needed in the teaching and learning of a particular topic.

Introducing the topic (in some plans only) outlines an approach to introducing the topic.

Lesson Interaction is set out under four sub-headings:

i. Student Learning Tasks – Teacher Input: This section focuses on teacher input and gives details of the key student tasks and teacher questions which move the lesson forward.

ii. Student Activities – Possible and Expected Responses: Gives details of possible student reactions and responses and possible misconceptions students may have.

iii. Teacher’s Support and Actions: Gives details of teacher actions designed to support and scaffold student learning.

iv. Checking Understanding: Suggests questions a teacher might ask to evaluate whether the goals/learning outcomes are being/have been achieved. This evaluation will inform and direct the teaching and learning activities of the next class(es).

Student Activities linked to the lesson(s) are provided at the end of each plan.

Page 3: Plan 10: Trigonometric Functions - Project Maths

© Project Maths Development Team 2009 www.projectmaths.ie 1

Teaching & Learning Plan 10: Trigonometric Functions

AimsTo help students to graph trigonometric functions sin • x, cos x and tan x

To recognise the period and range of each function•

To enable students to relate sin • x and cos x to the unit circle

To reinforce understanding of the terms function, domain, range, period, •inverse function, asymptote

Prior Knowledge Students should be familiar with the introduction to trigonometry (T&L Plan 8) and the unit circle (T&L Plan 9)

Learning OutcomesAs a result of studying this topic, students will be able to

plot the graph of • y= sin x, where x is an angle in standard position in the unit circle by projecting the y coordinates (sin x) of points on the unit circle onto an x-y Cartesian plane [This will be done for more than one revolution of the circle to emphasise the periodic nature of the functions. As small intervals are used the non linearity will be emphasised, and they will see that these graphs form smooth curves, which are “rounded” at the top and bottom.]

recognise the periodicity of • y = sin x, and be able to give the value of the period and the range

explain why • y = sin x is a function for all values of x and why its inverse is not a function for all values of x but could be if we restricted the x-values [more detail on this later in inverse functions]

solve equations of the form • , from the graph, for the domain plotted

plot the graph of • y= cos x by plotting the x coordinates of points on the unit circle against the corresponding angle in standard position, on an x-y Cartesian plane

plot graphs of sin • x, cos x and tan x using tables

plot graphs of the form • a sin x, a cos x and state their period and range, and explain the effect of changing the value of a

plot graphs of the form sin • bx, cos bx, state their period and range and explain the effect of changing the value of b

Page 4: Plan 10: Trigonometric Functions - Project Maths

Teaching & Learning Plan 10: Trigonometric Functions

© Project Maths Development Team 2009 www.projectmaths.ie 2

state the period and range of graphs of the form • asin bx, acos bx for a, b ∈ N

solve equations of the type • y = asin bx, y =acos bx for the domain used in the graph

sketch functions of the form • asin bx or a cos bx for a, b ∈ N from a knowledge of the period and range and the shape of the function

Relationship to Leaving Certificate Syllabus

Sub-topics Higher Level2.3 Trigonometry Graph the trigonometric functions sine, cosine, tangent.

Graph trigonometric functions of type asin nθ, acos nθ for a, n ∈ N.

Resources RequiredCompasses, protractors, clear rulers, pencils, formulae and tables booklet, Geogebra, Autograph, Perspex Model of Unit Circle (last 3 desirable but not essential)

Note

The CD icon is used throughout this document to indicate that there is a resource on the Student Disc relating to this topic.

Page 5: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

3

Less

on

In

tera

ctio

nSt

uden

t Le

arni

ng T

asks

: Te

ache

r In

put

Stud

ent A

ctiv

itie

s: P

ossi

ble

and

Expe

cted

Res

pons

esTe

ache

r’s S

uppo

rt a

nd

Act

ions

Chec

king

Und

erst

andi

ng

We

hav

e se

en o

n t

he

un

it

»ci

rcle

th

at s

in, c

os

and

tan

va

ry a

s th

e an

gle

var

ies

fro

m 0

° to

360

°. T

he

sin

fu

nct

ion

is r

epre

sen

ted

by

the

y co

ord

inat

e o

n t

he

un

it c

ircl

e.

Sho

w

»h

ttp

://w

ww

.p

roje

ctm

ath

s.ie

/sys

tem

/fi

les/

Pres

enta

tio

n%

20Lo

nd

on

%20

eye%

20si

ne.

pp

tx a

nd

Per

spex

Mo

del

of

un

it c

ircl

e.

Do

es t

his

pre

sen

tati

on

»

hel

p s

tud

ents

in t

he

task

of

plo

ttin

g t

he

gra

ph

y=

sin

x?

Usi

ng

»

Stu

den

t A

ctiv

ity

1A,

pro

ject

th

e va

lues

of

the

y co

ord

inat

e, w

hic

h is

sin

x

on

to t

he

Car

tesi

an p

lan

e to

g

et a

gra

ph

of

y= s

in x

0

≤ x

≤ 57

Stu

den

ts p

lot

the

po

ints

»

and

join

th

em in

a s

mo

oth

cu

rve.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

1. Tell

stu

den

ts t

hey

will

nee

d

»a

clea

r ru

ler

and

pen

cil.

Des

crib

e th

e g

rap

h

»St

ud

ent

Act

ivit

y 1B

Q 1

.It

co

nsi

sts

of

rep

eati

ng

pat

tern

s.

It h

as a

max

of

•1

and

a m

in

of

-1.

The

gra

ph

is “

rou

nd

ed”

– •

no

sh

arp

po

ints

.

Ask

ind

ivid

ual

stu

den

ts t

o

»d

escr

ibe

the

gra

ph

in t

hei

r o

wn

wo

rds.

Page 6: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

4

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng U

nder

stan

ding

Sho

w a

n a

nim

atio

n o

f th

is

»ex

erci

se f

rom

Au

tog

rap

h.

(File

, New

Ext

ras

Pag

e,

Trig

on

om

etry

, sin

)

See

also

(sc

roll

to e

nd

of

»p

age)

pis

ton

an

imat

ion

: h

ttp

://w

ww

.intm

ath

.co

m/

Trig

on

om

etri

c-g

rap

hs/

2_G

rap

hs-

sin

e-co

sin

e-p

erio

d.

ph

p

»G

eoG

ebra

inte

ract

ive

web

pag

e f(

x) =

asin

x. S

et

slid

er w

ith

a=

1

Do

es t

he

anim

atio

n

»su

mm

aris

e th

e ex

erci

se f

or

stu

den

ts a

nd

giv

e th

em

incr

ease

d u

nd

erst

and

ing

of

the

rela

tio

nsh

ip b

etw

een

si

n x

an

d t

he

y-co

ord

inat

e o

n t

he

un

it c

ircl

e?

An

y fu

nct

ion

wh

ich

is

»re

pea

tin

g s

uch

th

at f(

x)

= f(

x+c)

, w

her

e c

is a

co

nst

ant

is c

alle

d a

per

iod

ic

fun

ctio

n.

We

refe

r to

th

e le

ng

th o

f »

the

rep

eati

ng

pat

tern

on

th

e x-

axi

s as

th

e p

erio

d

and

th

e m

ax a

nd

min

y

valu

es a

re t

he

ran

ge

wri

tten

as

[min

val

ue, m

ax v

alue

]

Wri

te d

ow

n t

he

per

iod

an

d

»ra

ng

e o

f y=

sinx

Stu

den

t A

ctiv

ity

1B Q

2 a

nd

3.

Peri

od

= 3

60°

•R

ang

e =

[-1,

1]

Page 7: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

5

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng U

nder

stan

ding

Is

»y=

sin

x a

fun

ctio

n?

Stu

den

t A

ctiv

ity

1B Q

4

Stu

den

ts e

xpla

in in

Stu

den

t A

ctiv

ity

1B Q

4 th

at f

or

each

val

ue

of

x th

ere

is

on

ly o

ne

valu

e o

f y,

hen

ce

y=si

n x

is a

fu

nct

ion

.

Is t

he

inve

rse

of

»y=

sin

x a

fun

ctio

n?

Stu

den

t A

ctiv

ity

1B Q

5.

Exp

lain

yo

ur

answ

er.

»

Stu

den

ts e

xpla

in t

hat

fo

r »

any

y va

lue

ther

e is

an

in

fin

ite

nu

mb

er o

f x

valu

es,

so t

he

inve

rse

of

y=si

n x

is

no

t a

fun

ctio

n.

They

may

als

o d

raw

a

»h

ori

zon

tal l

ine

thro

ug

h

any

valu

e o

f y

in t

he

ran

ge,

sh

ow

ing

th

at it

has

m

ult

iple

so

luti

on

s.

Rem

ind

stu

den

ts t

hat

a

»fu

nct

ion

is a

set

of

ord

ered

p

airs

, wh

ere

each

x v

alu

e h

as o

ne

un

iqu

e y

valu

e.

Do

stu

den

ts r

emem

ber

»

wh

at a

fu

nct

ion

is?

Can

th

ey e

xpla

in w

hy

the

»in

vers

e o

f y=

sin

x is

no

t a

fun

ctio

n?

Co

mp

lete

»

Stu

den

t A

ctiv

ity

1B Q

6 an

d 7

.C

an s

tud

ents

so

lve

the

»eq

uat

ion

sin

x=0.

5?H

avin

g s

een

th

e co

nn

ecti

on

»

bet

wee

n y

= s

inx

and

m

oti

on

in a

cir

cle,

we

will

n

ow

plo

t th

e g

rap

h o

f y=

sin

x u

sin

g a

tab

le o

f va

lues

, th

en y

= 2

sin

x an

d

y= 3

sin

x, u

sin

g t

he

sam

e ax

es a

nd

sca

le.

Stu

den

ts p

lot

the

»g

rap

hs

on

gra

ph

pap

er

acco

mp

anyi

ng

Stu

den

t A

ctiv

ity

2 u

sin

g d

iffe

ren

t co

lou

rs f

or

each

gra

ph

.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

2.

Page 8: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

6

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

Act

ions

Chec

king

Und

erst

andi

ng

Wh

at is

th

e ef

fect

of

»va

ryin

g a

? St

ud

ent

Act

ivit

y 2.

The

ran

ge

chan

ges

. Th

e •

ran

ge

is [

-a, a

]If

req

uir

ed g

ive

stu

den

ts s

om

e h

elp

»

in m

akin

g t

his

co

ncl

usi

on

.D

o a

ll st

ud

ents

»

un

der

stan

d t

hat

in t

he

equ

atio

n y

=a

sin

x

the

per

iod

rem

ain

s u

nch

ang

ed a

s a

chan

ges

an

d t

hat

on

ly t

he

ran

ge

chan

ges

?

If t

his

was

a s

ou

nd

»

wav

e w

hat

eff

ect

do

yo

u t

hin

k it

wo

uld

hav

e o

n t

he

sou

nd

to

ch

ang

e th

e va

lue

of

a?

The

volu

me

wo

uld

incr

ease

as a

incr

ease

d.

In t

he

fun

ctio

n

»y=

a si

n bx

we

hav

e se

en t

he

effe

ct o

f va

ryin

g a

, an

d n

ow

we

will

kee

p a

co

nst

ant

at

a=1,

an

d v

ary

b.

Stu

den

ts fi

ll in

th

e ta

ble

»

and

plo

t th

e g

rap

hs

in 3

d

iffe

ren

t co

lou

rs (

Stu

den

t A

ctiv

ity

3).

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

3.

Rem

ind

stu

den

ts t

hat

th

ey a

re

»p

lott

ing

th

e fu

nct

ion

s

f : x

→ si

n x

g

: x →

sin

2x

h : x

→ si

n 3x

Are

stu

den

ts k

eep

ing

»

the

corr

ect

shap

e o

n t

he

curv

es e

ven

wh

en t

hey

h

ave

few

er p

oin

ts t

o p

lot

for

each

cyc

le?

Fill

in

»St

ud

ent

Act

ivit

y 3.

Wh

at is

th

e ef

fect

of

»va

ryin

g b

?

Stu

den

ts fi

ll in

»

Stu

den

t A

ctiv

ity

3.

As

•b

vari

es t

he

per

iod

va

ries

.

Stu

den

ts s

ho

uld

be

able

to

mo

ve

»fr

om

th

e sp

ecifi

c to

th

e g

ener

al

her

e an

d s

ho

uld

be

allo

wed

to

try

it

ou

t o

n t

hei

r o

wn

firs

t.

»U

sin

g G

eoG

ebra

inte

ract

ive

web

pag

e sh

ow

gra

ph

of

y=a

sin

b x

, var

yin

g a

an

d b

usi

ng

th

e sl

ider

s.

Page 9: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

7

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng U

nder

stan

ding

Ho

w c

an y

ou

cal

cula

te t

he

»p

erio

d g

iven

b?

Wh

en

•b

is 1

, th

e p

erio

d is

rad

= 3

60°.

Wh

en b

=2

the

per

iod

is π

rad

= 1

80°.

In g

ener

al t

he

per

iod

is

Can

stu

den

ts n

ow

cal

cula

te

»th

e p

erio

d a

nd

ran

ge

of

any

fun

ctio

n o

f th

e ty

pe

y=a

sin

bx, f

rom

th

e va

lues

o

f a

and

b?

Use

exa

mp

les

of

fun

ctio

ns

»o

f th

is t

ype

to c

hec

k.

If t

his

was

a s

ou

nd

wav

e »

wh

at w

ou

ld b

e th

e ef

fect

o

f va

ryin

g b

?

No

te: S

tude

nts

do n

ot n

eed

to

know

thi

s fo

r th

e sy

llabu

s, b

ut it

is

goo

d fo

r re

al li

fe c

onte

xt.

The

freq

uen

cy a

nd

hen

ce

•th

e p

itch

of

the

no

te w

ou

ld

chan

ge,

incr

easi

ng

as

b in

crea

sed

.

We

saw

ho

w s

in

»x

is t

he

y-co

ord

inat

e o

f a

po

int

on

th

e ci

rcu

mfe

ren

ce o

f th

e

un

it c

ircl

e an

d t

hat

co

s x

is

the

x-co

ord

inat

e. H

ence

by

plo

ttin

g t

he

x co

ord

inat

es

of

po

ints

on

th

e u

nit

cir

cle

on

to a

Car

tesi

an p

lan

e w

e sh

ou

ld g

et t

he

gra

ph

of

y=co

s x.

Sho

w a

n a

nim

atio

n o

f th

is

»ex

erci

se f

rom

Au

tog

rap

h.

(File

, New

Ext

ras

Pag

e,

Trig

on

om

etry

, co

s) a

nd

Pe

rsp

ex m

od

el o

f u

nit

ci

rcle

.

»Sh

ow

, usi

ng

a

Geo

Geb

ra in

tera

ctiv

e w

ebp

age,

wh

ere

sin

is

dra

gg

ed 9

0° t

o t

he

left

g

ivin

g t

he

cosi

ne

fun

ctio

n.

Page 10: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

8

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng U

nder

stan

ding

Des

crib

e th

e g

rap

h o

f

»y

= c

os x

Its

shap

e is

th

e sa

me

as t

he

•si

ne

gra

ph

. It

is t

he

gra

ph

o

f si

n x

shif

ted

90°

to

th

e le

ft.

It is

per

iod

ic w

ith

a p

erio

d

•o

f 36

0° a

nd

a r

ang

e o

f [-

1,1]

Are

stu

den

ts n

ow

ab

le t

o

»d

escr

ibe

the

gra

ph

of

y

= c

os x

in t

erm

s o

f p

erio

dic

ity

and

ran

ge,

hav

ing

wo

rked

wit

h

y = si

n x?

Hav

ing

see

n t

he

con

nec

tio

n

»b

etw

een

y =

cos

x a

nd

m

oti

on

in a

cir

cle,

we

will

n

ow

plo

t th

e g

rap

h o

f

y =

cos

x u

sin

g a

tab

le o

f va

lues

, th

en y

= 2

cosx

an

d

y =

3co

sx, u

sin

g t

he

sam

e ax

es a

nd

sca

le (

Stu

den

t A

ctiv

ity

4).

Stu

den

ts p

lot

the

gra

ph

s »

usi

ng

dif

fere

nt

colo

urs

fo

r ea

ch g

rap

h.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

4.

Wh

at is

th

e p

erio

d a

nd

»

ran

ge

of

y =

cos

x,

y =

2co

sx

and

y =

3co

sx?

Stu

den

t A

ctiv

ity

4.

Stu

den

ts fi

ll in

»

Stu

den

t A

ctiv

ity

4.D

o a

ll st

ud

ents

un

der

stan

d t

hat

»

in t

he

equ

atio

n y

= a

cos x

, th

e p

erio

d r

emai

ns

un

chan

ged

as

a ch

ang

es a

nd

th

at o

nly

th

e ra

ng

e ch

ang

es?

Wh

at is

th

e ef

fect

of

»va

ryin

g a

? St

ud

ent

Act

ivit

y 4.

The

ran

ge

chan

ges

. Th

e •

ran

ge

is [

-a,a

]

In t

he

fun

ctio

n

»y=

a co

s bx

we

hav

e se

en t

he

effe

ct o

f va

ryin

g a

, an

d n

ow

we

will

ke

ep a

co

nst

ant

and

var

y b.

Stu

den

ts fi

ll in

th

e ta

ble

and

plo

t th

e g

rap

hs

in 3

d

iffe

ren

t co

lou

rs. S

tud

ent

Act

ivit

y 5.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

5.A

re s

tud

ents

kee

pin

g t

he

»co

rrec

t sh

ape

on

th

e cu

rves

ev

en w

hen

th

ey h

ave

few

er

po

ints

to

plo

t fo

r ea

ch c

ycle

?

Page 11: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

9

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

Act

ions

Chec

king

Und

erst

andi

ng

Wh

at is

th

e p

erio

d a

nd

»

ran

ge

of

y =

cos

x

y =

cos

2x

and

y =

cos

3x?

St

ud

ent

Act

ivit

y 5.

Wh

at is

th

e ef

fect

of

vary

ing

»

b?

Stu

den

ts fi

ll in

»

Stu

den

t A

ctiv

ity

5.

As

•b

vari

es t

he

per

iod

va

ries

.

Ho

w c

an y

ou

cal

cula

te t

he

»p

erio

d g

iven

b?

Wh

en

•b

is 1

, th

e p

erio

d is

rad

= 3

60°.

Wh

en b

=2

the

per

iod

is π

rad

= 1

80°.

In g

ener

al t

he

per

iod

is

Stu

den

ts m

ay n

eed

so

me

hel

p

»in

mo

vin

g f

rom

th

e sp

ecifi

c to

th

e g

ener

al h

ere;

allo

w t

hem

to

try

it o

ut

on

th

eir

ow

n fi

rst.

Can

stu

den

ts n

ow

»

calc

ula

te t

he

per

iod

an

d

ran

ge

of

any

fun

ctio

n

of

the

typ

e y=

a co

s bx,

fr

om

th

e va

lues

of

a an

d

b?

Use

mo

re e

xam

ple

s o

f »

fun

ctio

ns

of

this

typ

e to

ch

eck

un

der

stan

din

g.

Sket

ch t

he

gra

ph

s o

f th

e »

fun

ctio

ns

on

Stu

den

t A

ctiv

ity

6, w

ith

ou

t ta

ble

s o

f va

lues

, by

firs

t ca

lcu

lati

ng

th

e p

erio

d a

nd

ran

ge,

an

d k

no

win

g t

he

shap

e o

f fu

nct

ion

s o

f th

e ty

pe

y=a

sin

bx a

nd

y=a

cos b

x.

Stu

den

ts m

ake

4 ev

enly

»

spac

ed m

arks

on

th

e

x ax

is a

nd

mar

k th

e ra

ng

e o

n t

he

y ax

is, a

nd

p

lot

the

curv

es.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

6.

Wal

k ar

ou

nd

, lo

oki

ng

at

the

»g

rap

hs,

ref

erri

ng

stu

den

ts b

ack

to t

he

pre

vio

us

acti

vity

sh

eets

w

hen

th

ey a

re in

do

ub

t.

»Sh

ow

Geo

Geb

ra in

tera

ctiv

e w

ebp

age

y=a

sin

bx a

nd

y=a

cos b

x

Are

stu

den

ts a

ble

to

»

sket

ch g

rap

hs

of

the

form

y=a

sin

bx a

nd

y=

a co

s bx

fro

m t

he

valu

es o

f p

erio

d a

nd

ra

ng

e?

We

will

no

w lo

ok

at t

he

»g

rap

h o

f th

e fu

nct

ion

y=

a ta

n x.

Dis

trib

ute

»

Stu

den

t A

ctiv

ity

7.

Page 12: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

10

Stud

ent

Lear

ning

Tas

ks: T

each

er

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng

Und

erst

andi

ngW

hat

is t

he

rela

tio

nsh

ip

»b

etw

een

sin

, co

s an

d t

an o

f an

an

gle

x?

Wh

at m

easu

rem

ent

in t

he

»d

iag

ram

rep

rese

nts

fo

r in

stan

ce

the

tan

<A

OA

’’? E

xpla

in.

Tan

<A

OA

’’ =

inte

rcep

t th

e •

rad

ius

fro

m O

to

A’’

cuts

off

th

e lin

e x=

1.

Fill

in t

he

tab

le o

n

»St

ud

ent

Act

ivit

y 7A

.St

ud

ents

fill

in

»St

ud

ent

Act

ivit

y 7A

.

Stu

den

ts p

lot

the

po

ints

. »

(Stu

den

t A

ctiv

ity

7B)

Usi

ng

a c

alcu

lato

r, fi

nd

tan

89°

, »

then

th

e ta

n 8

9.99

9°, t

hen

th

e ta

n 8

9,99

999°

.

Wh

at is

th

e ta

n 9

1°, 9

0.00

1°,

»an

d 9

0.00

001°

?

57.2

9, 5

7295

.78,

572

9577

.951

-57.

29, -

5729

5.78

,-57

2957

7.95

Stu

den

ts w

ho

may

hav

e »

dif

ficu

lty

un

der

stan

din

g

that

tan

x t

end

s to

infi

nit

y ca

n b

e h

elp

ed in

th

is b

y u

sin

g t

he

calc

ula

tor

to

eval

uat

e ta

n o

f an

gle

s ve

ry

clo

se t

o 9

0°.

Do

stu

den

ts s

ee t

hat

»

as x

get

s cl

ose

r to

90

°, t

an x

incr

ease

s ve

ry r

apid

ly?

Des

crib

e th

e g

rap

h o

f

»y

= ta

n x?

Its

shap

e is

un

like

the

gra

ph

s •

of

y =

sin

x an

d y

= c

os x

.

Ther

e ar

e g

aps

in it

. •

It is

per

iod

ic b

ut

it r

epea

ts

•m

ore

oft

en t

han

sin

x o

r co

s x

Stu

den

ts c

om

ple

te

»St

ud

ent

Act

ivit

y 7C

.

Enco

ura

ge

stu

den

ts t

o

»d

escr

ibe

the

gra

ph

in t

hei

r o

wn

wo

rds,

bu

t b

ecau

se

of

fam

iliar

ity

wit

h s

in a

nd

co

s g

rap

hs

they

sh

ou

ld b

e u

sin

g t

he

wo

rds

per

iod

an

d

ran

ge.

Wh

at is

th

e p

erio

d

»y

= ta

n x?

(St

ud

ent

Act

ivit

y 7C

)It

s p

erio

d is

180

°.•

Page 13: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

11

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng U

nder

stan

ding

Des

crib

e h

ow

tan

»

x va

ries

as

x a

pp

roac

hes

90°

?

As

the

ang

le a

pp

roac

hes

90°,

tan

x in

crea

ses

very

ra

pid

ly a

nd

ten

ds

to +

∞ a

s it

ap

pro

ach

es 9

0° f

rom

th

e le

ft,

and

to

- ∞

as

it a

pp

roac

hes

90

° fr

om

th

e ri

gh

t.

»Sh

ow

th

e G

eoG

ebra

in

tera

ctiv

e w

ebp

age

on

y=

tan

x

Do

stu

den

ts a

pp

reci

ate

»th

e p

hra

se “

ten

ds

to

infi

nit

y” a

s x

ten

ds

to

90°?

Wh

at is

th

e ra

ng

e o

f »

y =

tan

x (S

tud

ent

Act

ivit

y 7C

).

[-∞

,+∞

]•

Are

stu

dent

s ab

le t

o pl

ot t

he

grap

h of

y =

tan

x an

d lis

t th

e pe

riod

and

rang

e?

Wh

at is

th

e ta

n 9

0°?

»U

nd

efin

ed•

The

gra

ph

of

»y

= ta

n x

app

roac

hes

a li

ne

as x

ap

pro

ach

es f

or

exam

ple

, 90

° an

d 2

70°.

Th

ese

lines

ar

e ca

lled

ASY

MPT

OTE

S –

a st

raig

ht

line

to w

hic

h t

he

gra

ph

bec

om

es c

lose

r an

d

clo

ser

bu

t d

oes

n’t

to

uch

.

Dra

w in

th

e as

ymp

tote

s o

n

»th

e g

rap

h.

Stu

den

ts d

raw

in li

nes

»

y =

–90

° y

= 9

y =

270

°

Page 14: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

KE

Y:

» n

ext

step

stud

ent

answ

er/r

espo

nse

12

Stud

ent

Lear

ning

Tas

ks:

Teac

her

Inpu

tSt

uden

t Act

ivit

ies:

Pos

sibl

e an

d Ex

pect

ed R

espo

nses

Teac

her’s

Sup

port

and

A

ctio

nsCh

ecki

ng

Und

erst

andi

ngR

eflec

tio

nW

rite

do

wn

3 t

hin

gs

you

»

lear

ned

ab

ou

t to

day

tr

igo

no

met

ric

fun

ctio

ns.

Wri

te d

ow

n a

nyt

hin

g y

ou

»

fou

nd

dif

ficu

lt.

Wri

te d

ow

n a

ny

qu

esti

on

s »

you

may

hav

e.

Dra

w t

he

gra

ph

of

sin

1.

x,

a

sin

x, s

in b

x an

d a

sin

bx.

Fin

d t

he

per

iod

an

d r

ang

e o

f si

n

2.

x,

a si

n x

, sin

bx

and

a s

in b

x.

Co

nce

pt

of

vary

ing

3.

a

and

b in

y

= a

sin

bx

Dra

w t

he

gra

ph

of

cos

4.

x,

a co

s x,

co

s bx

an

d a

co

s bx

.

Fin

d t

he

per

iod

an

d r

ang

e o

f co

s 5.

x,

a

cos

x, c

os

bx a

nd

a c

os

bx.

Co

nce

pt

of

vary

ing

6.

a

and

b in

y

= a

co

s bx

Dra

w t

he

gra

ph

of

7.

y

= t

an x

.

Fin

d t

he

per

iod

an

d r

ang

e o

f ta

n

8.

x.

Co

nce

pt

of

asym

pto

tes

9.

Dra

w a

sym

pto

tes

on

th

e g

rap

h

10. y

= t

an x

.

Cir

cula

te a

nd

tak

e »

no

te p

arti

cula

rly

of

any

qu

esti

on

s st

ud

ents

h

ave

and

hel

p t

hem

to

an

swer

th

em.

Hav

e al

l stu

den

ts

»le

arn

ed a

nd

u

nd

erst

oo

d t

hes

e it

ems?

Are

th

ey u

sin

g t

he

»te

rmin

olo

gy

wit

h

un

der

stan

din

g a

nd

co

mm

un

icat

ing

wit

h

each

oth

er u

sin

g t

hes

e te

rms?

Page 15: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

13

Stud

ent A

ctiv

ity

1Stu

den

t A

ctiv

ity 1

AG

raph

of y

= sin

x C

ompl

ete

the

proj

ectio

n of

sin

val

ues

from

the

unit

circ

le o

nto

the

Car

tesia

n pl

ane

on th

e rig

ht a

nd th

en jo

in th

e po

ints

with

a s

moo

th c

urve

.

Stu

den

t A

ctiv

ity 1

B1.

Des

crib

e th

e g

rap

h o

f y

= s

in x

. __

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

2. W

hat

is t

he

per

iod

of

y =

sin

x?

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

___

3. W

hat

is t

he

ran

ge

of

y =

sin

x?

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

4. I

s y

= s

in x

a f

un

ctio

n?

Exp

lain

. ___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

5. I

s th

e in

vers

e o

f y

= s

in x

a f

un

ctio

n?

Exp

lain

. __

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

6. U

sin

g t

he

gra

ph

so

lve

for

x th

e eq

uat

ion

sin

x =

0.5

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

7. H

ow

man

y so

luti

on

s h

as t

he

equ

atio

n in

Q6?

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

___

Page 16: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

14

Stud

ent A

ctiv

ity

2

Usin

g a

calc

ulat

or, o

r the

uni

t circ

le, fi

ll in

the

tabl

e fo

r the

follo

win

g gr

aphs

and

plo

t all

of th

em u

sing

the

sam

e ax

es.

y = si

n x,

y = 2

sin x,

y =

3sin

x U

se d

iffer

ent c

olou

rs fo

r eac

h gr

aph.

x/º

-90

-60

-30

030

6090

120

150

180

210

240

270

300

330

360

sin

x2s

in x

3sin

x

Peri

odRa

nge

y =

sin

xy

= 2

sin

xy

= 3

sin

xy

= a

sin

x

In

th

e fu

nct

ion

, wh

at is

th

e ef

fect

on

th

e g

rap

h o

f va

ryin

g a

in a

sin

x?

____

____

____

____

____

____

____

____

____

____

____

____

____

___

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

Page 17: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

15

Stud

ent A

ctiv

ity

3

Fill

in th

e ta

ble

first

, and

usin

g th

e sa

me

axes

but

diff

eren

t col

ours

for e

ach

grap

h, d

raw

the

grap

hs o

f:y =

sin

x, y =

sin

2x =

sin

(2 x

x), y

= si

n 3x

= si

n (3

x x)

G

raph

s of

the

form

y =

sin b

x

x/º

015

3045

6075

9010

512

013

515

016

518

019

521

022

524

025

527

028

530

031

533

034

536

0

sin

x2x si

n 2x

3x sin

3x

Peri

odRa

nge

y =

sin

xy

= si

n 2x

y =

sin

3xy

= si

n bx

In

th

e g

rap

h o

f y

= si

n bx

, wh

at is

th

e ef

fect

on

th

e g

rap

h o

f va

ryin

g b

in si

n bx

? ___

____

____

____

____

____

____

____

____

____

____

___

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

Page 18: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

16

Stud

ent A

ctiv

ity

4

Usin

g a

tabl

e, fi

nd th

e co

ordi

nate

s fo

r the

follo

win

g gr

aphs

and

plo

t all

of th

em u

sing

the

sam

e ax

es: y

= co

s x, y

= 2

cos x

, y =

3co

s x

x/º

-90

-60

-30

030

6090

120

150

180

210

240

270

300

330

360

cos x

2cos

x3c

os x

Peri

odRa

nge

y =

cos

xy

= 2

cos x

y =

3co

s x

In

th

e fu

nct

ion

y =

acos

x ,

wh

at is

th

e ef

fect

on

th

e g

rap

h o

f va

ryin

g a

in a

cos x

? __

____

____

____

____

____

____

____

____

____

____

___

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

Page 19: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

17

Stud

ent A

ctiv

ity

5

By fi

lling

in a

tabl

e fir

st, a

nd u

sing

the

sam

e ax

es b

ut d

iffer

ent c

olou

rs fo

r eac

h gr

aph,

dra

w th

e gr

aphs

of

x/º

015

3045

6075

9010

512

013

515

016

518

019

521

022

524

025

527

028

530

031

533

034

536

0

cos x

2x cos 2

x3x co

s 3x

Peri

odRa

nge

y =

cos

xy

= c

os 2

xy

= c

os 3

xy

= c

os b

x

In

th

e g

rap

h o

f y

= ac

os b

x, w

hat

is t

he

effe

ct o

n t

he

gra

ph

of

vary

ing

b in

cos

bx?

____

____

____

____

____

____

____

____

____

____

____

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

___

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

_

Page 20: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

18

Stud

ent A

ctiv

ity

6

Sket

ch e

ach

of

the

follo

win

g g

rap

hs:

(0°

≤ x

≤ 36

0°)

y

= 4

sin

x

Pe

rio

d =

____

____

____

____

_ R

ang

e =

____

____

____

____

_

Sket

ch e

ach

of

the

follo

win

g g

rap

hs:

(0°

≤ x

≤ 36

0°)

y

= c

os4

x

Pe

rio

d =

____

____

____

____

_ R

ang

e =

____

____

____

____

_

Sket

ch e

ach

of

the

follo

win

g g

rap

hs:

(0°

≤ x

≤ 36

0°)

y

= 2

sin

3x

Per

iod

=__

____

____

____

___

Ran

ge

=__

____

____

____

___

Page 21: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

19

Stud

ent A

ctiv

ity

7

Stu

den

t A

ctiv

ity 7

A

|∠AO

A’|

|∠AO

A’’|

|∠AO

A’’’|

|∠AO

A’’’’

||∠

AOA’

’’’’|

30.0

0°60

.00°

75.0

0°80

.00°

85.0

y=ta

n x

Usi

ng

th

e d

iag

ram

of

the

un

it c

ircl

e, r

ead

th

e ap

pro

xim

ate

valu

e o

f th

e ta

n o

f th

e an

gle

s in

the

tab

le u

sin

g t

he

trig

on

om

etri

c ra

tio

s.

Ang

le θ

/º0

3060

7580

85ta

n θ

Page 22: Plan 10: Trigonometric Functions - Project Maths

Teac

hing

& L

earn

ing

Plan

10:

Tri

gono

met

ric

Func

tion

s

© P

roje

ct M

aths

Dev

elop

men

t Tea

m 2

009

w

ww

.pro

ject

mat

hs.ie

20

Stud

ent A

ctiv

ity

7

Stu

den

t A

ctiv

ity 7

B

By fi

lling

in a

tabl

e fir

st, a

nd u

sing

the

sam

e ax

es b

ut d

iffer

ent c

olou

rs fo

r eac

h gr

aph,

dra

w th

e gr

aphs

of

x/º

-90

-75

-60

-45

-30

030

4560

7590

105

120

135

150

180

210

225

240

255

270

285

300

330

360

tan

x

Stu

den

t A

ctiv

ity 7

C

y =

tan

xPe

riod

Rang

e