# 1TTO §6.5 Comparing graphs PART TWO PTI

§7.5 Comparing graphs PART TWO
Many time a movie gets a sequel (=vervolg),
as in 'Home alone 2'.
The new one is not always better than the first film.
Let's hope for the best for this LessonUp ...
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

This lesson contains 30 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

§7.5 Comparing graphs PART TWO
Many time a movie gets a sequel (=vervolg),
as in 'Home alone 2'.
The new one is not always better than the first film.
Let's hope for the best for this LessonUp ...

#### Slide 1 -Slide

PART TWO ......
is about p.223 and 224 the 2nd part of  §7.5 Comparing graphs.

#### Slide 2 -Slide

First let's look back at one Homework exercise:
number 33, p.223 is the one!

#### Slide 3 -Slide

8

Task 1: Give your answer to 33a in the next slide.

#### Slide 4 -Slide

Solution Task 1: (33a)

#### Slide 5 -Slide

Task 1: Jean's better off ...
A
with Vital
B
it depends
C
with Hydro
D
this is not clear

#### Slide 6 -Quiz

Give your answer to 33b in the next slide.
Watch the vital word: 'INCREASE'!

A
225
B
200
C
35
D
165

#### Slide 8 -Quiz

Solution Task 2: (33b)

What is the number 200 doing in the calculation?
For more than 200 cubed metres Vital is cheaper.
So, to explain it a little differently: for more than 165 + 35 = 200 cubed metres
Vital is cheaper, so the answer is:  a 35 cubed metres INCREASE!

#### Slide 9 -Slide

We go on with 2 graphs in one coordinate system.
In PART ONE the emphasis (=nadruk) was on comparing them.
Now we concentrate on the POINT OF INTERSECTION (p.o.i) of both graphs!

#### Slide 10 -Slide

Read off the p.o.i. of both
graphs.
Key in in next slide.

#### Slide 11 -Slide

task 3: The p.o.i. is .......
A
(5, 4)
B
(3 1/2, 5)
C
(5, 3.5)
D
(5, 3 1/2)

#### Slide 12 -Quiz

Read off the p.o.i. of both
graphs.
Key in in next slide.
Explanation:
First we write down the HORIZONTAL
coordinate; only then the VERTICAL one.
So we get:  (5, 3  1/2)   or   (5, 3.5)   Don't forget the brackets!

#### Slide 13 -Slide

There are 2 ways to get to know the points of intersection:

Reading off  p.o.i.      -         Calculating p.o.i.
But ...... when to do what?!

#### Slide 14 -Slide

Why calculating, if you can read off ??!
Many times the p.oi. from 2 graphs is hard to read off.
For instance:
you read off (3, 7) but in fact the p.o.i. turns out to be
(3.1 , 6,9) !
In fact CALCULATING is more exact -better- than reading off.

#### Slide 15 -Slide

From READING OFF we now move to CALCULATING the p.o.i.!

#### Slide 17 -Slide

Task 4:  Fill in number = 5 in the green formula.

The green graph has this formula:
6 - number x 0.5 = length
On paper fill in number = 5 in this formula.
Take a pic of your CALCULATION and send it in, in the
next slide!

#### Slide 18 -Slide

Fill in number = 5 in green formula.

#### Slide 19 -Open question

Solution Task 4:  Fill in number = 5 in the green formula.

#### Slide 20 -Slide

Task 5:  Fill in number = 5 in the red formula.

From the graph you can read off the red formula too:
number x 0.5 + 1 = length

On paper fill in number = 5 in this formula.
Key in your CALCULATION in the next slide.

#### Slide 21 -Slide

Fill in 'number = 5'
in number x 0.5 + 1 = length

#### Slide 23 -Slide

Explanation Task 5:  Fill in number = 5 in the red formula.

The green formula :
number x 0.5 + 1 = length

#### Slide 24 -Slide

Summarising (1)  what we just did:

Summarising (2):

#### Slide 26 -Slide

Task 6: In order to do 35a and 36, what should you do first? Answer in next slide.
timer
0:15

#### Slide 27 -Slide

What to do first?