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**.

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.

Materials ....

+ Take before you the right things:

+ pencil, pen, geo triangle or ruler, eraser

+ Notebook and Textbook 1A

7

This is the Theory.

Next slide shows us an example.

5

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

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.

Question about this task:

What to do first, before plotting the graph?

Answer in next slide.

First you ....

Solution:

First you ...

MAKE A TABLE !

As follows:

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

A zigzag: a good idea? (Why?)

A

no

B

yes

Solution:

(By the way: the Solutionsbook does NOT do this!)

Think about this for half a minute.

For the answer see next slide.

timer

0:30

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.

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!

Send in you graph!

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.'

What special point of both graphs is meant in this question?

Answer in the next slide.

The special point is ....?

Solution:

the point of intersection

Next slide explains us how you can

see from the Formula if the Graph

is Rising or Falling.

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.

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