1TH Ch3 Summary learning goals p.112/117 (2)

• Wiskunde
• Middelbare school
• havo
• Leerjaar 1

Extra exercises, p.122/123 ...

is a good way to go through all content from Ch 4 Graphs once more, 

to get prepared for the test!

First we single out a few fine points.  

So, please open your Textbook and Notebook!     

TASK 1: Point E is (5, 8) or (8, 5) ?

Key in in next slide.

This is the graph 

from exercise E3:

What are the good coordinates?

1. (5, 8)
2. both are good
3. (8, 5)
4. neither are good

TASK 2:                        

STATEMENT:

 'There's a mistake in the graph below, because a ZIGZAG on the horizontal axis is missing. '             TRUE or FALSE?

Key in your answer 

in the next slide.

(This is exercise E4.)

True or False?
(Think about the reason for your choice!)

1. False
2. True

Explanation:

Only on a vertical axis we may use a ZIGZAG, not on a horizontal axis!

That's why the statement is false.

Time to work quietly on E1 - E13, p.112-117

Later a few more fine points are discussed!

Before you go on with E1 - E13

we have a look at some details again!

Talking about details,

Talking about scale ...

TASK 3:

What's a good scale for the horizontal axis?

1 cm = ... hours (key in in next slide)

1 cm = ..... hours

Solution:

Time in hours were: 6, 9, 12, 15, 18, 21 and 24 

They are all threesomes (= multiples of 3).

This means that 1 cm = 3 hours is clearly the best choice!

In that case the length of the axis will be:

(24 - 6) : 3 = 18 : 3 = 6 cm and that's all right. 

TASK 4:

What's a good scale for the vertical axis?

1 cm = ... temperature (key in in next slide)

A good scale is ....

1. 1 cm = 1 degree
2. 1 cm = 3 degrees
3. 1 cm = 2 degrees

Solution Task 4:

The temperature varies from 13.5 to 26 degrees. So 26 - 13.5 = 12.5 degrees have to be given a place on the vertical axis. Use a zigzag for 0 - 13 degrees.

+ if you take 1 cm = 1 degree, the the axis will be 12.5 : 1 = 12.5 so about 13 cm long. That's too long.

+  if you take 1 cm = 2 degrees, then the axis is 12.5 : 2  is about 6 cm. Fine too, although short.

+ Finally, taking 1 cm = 3 degrees, then the axis' length is 12.5 : 3 is about 4 and that's

   a bit too short.

Homework time!

DO:  extra exercises, p.122/123