1TH/vwo §11.4+§11.5 MORE PRACTICE!

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

But first...

Open your Notebook and take a

- pen, pencil, eraser 

- from your pencil case!

The coordinate system is something you have to KNOW.

Next is making a FORMULA for a STRAIGHT GRAPH.

This something you have to UNDERSTAND!

By the way, the homework will be just a few exercises.

You can only do them succesfully if you pick up the following content! 

2 things are important to know,

when making a formula for this graph: 

1st:  at what height does the graph go through the vertical axis?

2nd:  how much does it rise when going one step to the right?

Next slides show you the Method and an example, completely worked out!

Now it's your turn! Step by step.

Task 1                                   Step 1: Mention a GRID POINT in this graph in the next slide. Don't forget the brackets!

A grid point: (..., ...)

Grid points are:

(-1, 4) (0, 2) (1, 0) (2, -2)

So: no fractions, but whole numbers!

Task 2.  STEP 2:     Read off the start number. Key in in the next slide.

The start number is:

1. 0
2. -2
3. 2
4. -1

The start number is ..... 2!

At the height of 2 the graph goes through the

vertical axis. That's why!

Task 3:          Step 3:

Work out in your head how much the graph rises or falls per horizontal step of 1.

Key in in the next slide.

How much?

1. 2
2. -2
3. 1
4. 1/2

SOLUTION:                                 Task 3:          Step 3:

Work out in your head how much the graph rises or falls per horizontal step of 1.

Per step of 1 the graph falls by 2 steps.

So: the value of y decreases (=gets less)

by 2.

Task 4          Step 4:  Key in the right formula in the next slide.

The formula is:

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

 SOLUTION:   Task 4          Step 4:  Key in the right formula in the next slide.

We now fill in the numbers 

from steps 2 and 3:

y = -2x + 2   or 

y = 2 - 2x     or

2 - 2x = y

High time for a recap on §12.5 now, but ...

even higher time for a JOKE!

The last technique you have to know is this:

suppose you've got a Parabola and a Point given.

How can we find out -by Calculating!-  IF the point lies on the graph?!

NOTE: we don't draw the graph, to check it. Too much work

for us, lazy ones!

Task 4:

FOTOVRAAG:  Work this out in your Notebook, take a picture and send it in!

My Calculation:

Solution Task 4:

Watch the next slide too!

Addition:  From the Graph you can see that it is necessary to Calculate it, because x = -5 is not visible on the graph!!

Homework:

p.203:    In this order:       E7,   E8,   E5   

For  E7 and E8 you have to MAKE CALCULATIONS.       

An answer like 'Yes' or 'No' will not do.

At E5 produce a correct table and a beautiful graph!

 Use what you learnt in this lesson!