1TTO 12.4 Linear formulas

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 1

§12.4 Linear formulas

The main goal in this paragraph is: 

 Learning how to make a FORMULA for a LINEAR GRAPH!

First a Freshen Up Task. 

See next slide!

What is a linear graph?

A linear graph is a straight line

in a coordinate system.

Point of attention:

Everybody can learn how to make a formula for a linear graph.

However, it takes several steps - 4, in fact! - to do this.

So concentrate and work hard on all the coming slides.

Only then you will get to know 'the whole trick'! 

Take before you:

+ Notebook and Textbook 1B, p.182

+ From your pencil case: 

    pencil, pen, geo, eraser

Something new about the Coordinate system(1):

Something new about the Coordinate system (2):

Schermafbe

In which quadrant have you been working up to now?

1. 4
2. 3
3. 2
4. 1

Watch: the POSITIVE NUMBERS

are used for the 1st Quadrant.

And the 1st Quadrant is the one that

you've used up to now.

But this gonna change soon...

Now more about Formulas and Graphs:

Here you see the graph 

that belongs to the Formula!

Making a FORMULA for this graph...

is exactly what you're going to learn now!

We study the Method together now.

After this you are going to work out these steps yourself!

 om 19.56.

TASK:

Make a FORMULA for the GRAPH!

How?

+  Open your Notebook.

+  Open your Textbook on p.184 so you can look

     back at the METHOD

+  You're going WORK OUT the 4 STEPS that

    we just studied

Step 1=FOTOVRAAG (next slide)

Step 1:

Make a TABLE 

in your Notebook 

with values you can

read off exactly! 

(for this graph only 3 values for x and 3 for y)

Take a pic and send it in.

The TABLE (step 1):

Solution Step 1:

Step 2:
Read of the Start number.
Do this from the Table you made!

1. 6
2. 2
3. -6
4. 3

Solution Step 2:

The goes through the Vertical

axis at height -6. 

That's why.

The coordinates (0, -6) from the table

also give you this information.

Step 3:
How much does the graph rise or fall per horizontal step of 1?
Read this off from your Table.

1. 2
2. 3
3. -6
4. 6

Solution step 3:

Step 4:
The Formula is: ....................

1. y = 6x - 3
2. 3x - 6 = y
3. x = 3y - 6
4. y = - 6 + 3x

Solution step 4:

the Formula is:

y = 3x - 6                  or:             3x - 6 = y     

 or  also:                                      -6 + 3x = y

Looking back ....

- did you do great, or

- did you miss out on these tasks?

- most important is to try hard, so that you learn a lot,

- you probably really begin to understand it when doing your homework! 

Homework:

§ 12.4 Linear formulas: 27, 28 and 29.