# 1TH/vwo §7.2 Graphs from formulas

1TH/vwo §7.2 Graphs from formulas
(not 9, 10, 11 and 12 as we do a lot together)
Many TABLES to be made and many
GRAPHS to be drawn in this paragraph. Tired already? Me too!
First we do a part of the paragraph together.
If you participate well, you may SKIP a few exercises from the paragraph.
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Slide 1: Tekstslide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

In deze les zitten 29 slides, met interactieve quizzen en tekstslides. Lesduur is: 50 min

## Onderdelen in deze les

1TH/vwo §7.2 Graphs from formulas
(not 9, 10, 11 and 12 as we do a lot together)
Many TABLES to be made and many
GRAPHS to be drawn in this paragraph. Tired already? Me too!
First we do a part of the paragraph together.
If you participate well, you may SKIP a few exercises from the paragraph.

#### Slide 1 -Tekstslide

Materials ....
+ Take before you the right things:
+ pencil, pen, geo triangle or ruler, eraser
+ Notebook and Textbook 1A

#### Slide 2 -Tekstslide

7
This is the Theory.
Next slide shows us an example.

5

#### Slide 4 -Tekstslide

Steps of 60 is fine, because ...
A
you have to put 300 on the axis; then you need 300 : 60 = 5 cm.
B
the time goes from 0 to 5
C
the distances go up by 60 all the time
D
there is no zigzag needed

#### Slide 5 -Quizvraag

6
Points of attention:
+ Scale:  on the vertical axis 60 (km?) is put in 1 cm, so that you cover 300 km.
+ This time a straight line -not smooth- because all points lie on one line.
+ Labelling of the axes has not been forgotten.

#### Slide 6 -Tekstslide

What to do first, before plotting the graph?
Answer in next slide.

First you ....

Solution:
First you ...
MAKE A TABLE !
As follows:

#### Slide 9 -Tekstslide

4
You may skip exercises 9, 10 and 11.
Now:
MAKE 12a in your Notebook,  by copying and filling in the Table above!
In 2 minutes we look at the answers.
try to be ready by then!
timer
2:00

#### Slide 10 -Tekstslide

Before you go on with 12, there come a few questions about it.

Note: only the even number are used, because otherwise there would be 15 numbers...

#### Slide 12 -Tekstslide

Question 1: Is a 'zigzag' a good idea or not?

#### Slide 13 -Tekstslide

A zigzag: a good idea? (Why?)
A
no
B
yes

#### Slide 14 -Quizvraag

Solution:

Yes. Because the height only starts at 120 cm.
(By the way: the Solutionsbook does NOT do this!)

#### Slide 15 -Tekstslide

Question 2: What is a good scale for the corresponding Graph? Why?
For the answer see next slide.
timer
0:30

#### Slide 16 -Tekstslide

QUESTION: What is a good scale for the vertical axis
of the corresponding Graph?
SOLUTION: 260 - 120 = 140
140 : 20 = 7 , so if you use as a scale:
20 cm in table = 1 cm in graph, then you need 7 cm.
That's fine.

#### Slide 18 -Tekstslide

FOTOVRAAG
Now PLOT the GRAPH and send in a picture of your work in next slide. Remember:
1.  a zigzag at height 120 cm
2. scale on vertical axis: 20 cm in 1 cm.
Make your teacher happy: draw a beautiful graph!

#### Slide 19 -Tekstslide

Send in you graph!

#### Slide 21 -Tekstslide

In this exercise you can see that 2 Graphs are plotted, in THE SAME COORDINATE SYSTEM!
NOTE 1:   First a handy TIP about the Tables:
USE a DOUBLE TABLE - saves you some work. This is shown in the next slide!
NOTE 2:  An important remark in 13a is: 'Take the horizontal axis to 10.'

#### Slide 23 -Tekstslide

Question 3,         about d:
What special point of both graphs is meant in this question?
Answer in the next slide.

#### Slide 24 -Tekstslide

The special point is ....?

#### Slide 25 -Woordweb

Solution:
the point of intersection

Next slide explains us how you can
see from the Formula if the Graph
is Rising or Falling.

#### Slide 26 -Tekstslide

Above you first see explained: a rising graph.
Below a falling graph is explained.
Most important are the signs        +  and   -.
The minus sign before the multiplication means a falling graph!
Suppose the minus sign was before 60 it only meant that the graph starts
at a lower point. It says nothing about falling or rising.
Next slide says it in other words.

#### Slide 28 -Tekstslide

Homework time - skip 9, 10, 11 and 12,
because we did a lot together.
Do §7.2 now.
Both 13 and 14 contain TWO graphs. So use DOUBLE TABLES in both cases!
Plotting good Graphs, using a pencil and a geo/ruler.
1.make it
2.correct your work with the Solutionsbook
3.take pics and
4.send them in in GC