3Thavo §11A.2 and §11B2 Intervals

• Wiskunde
• Middelbare school
• havo
• Leerjaar 3

§ 11A.2 and § 11B.2 Intervals

In this paragraph you will learn ......

Let's do exercise 7 together.

+ Open your Notebook

+ Write down 7a in the margin and

+ work it out.

+ Finally key in your answer in the next slide!

The solution is:
A. (2, 1/3) B. 2.33
C. 2 1/3 D. 2.333

1. (2, 1/3)
2. 2.33
3. 2 1/3
4. 2.333

Solution 7a:

Note:

2.3   or  2.33 are not

exactly the same as 

2 1/3 !

For answering b), it is important to

+ remember that x = 2 1/3 was the 

   answer for a), and

+ use the graph! Key words are:

   'higher' and 'lower'.

+ in 30 seconds I will ask one of you for your answer.

answer:

The question was:

Explanation: for which x-values 

does the graph for y = 8 - x  lie

lower than that of y = 2x + 1 ?

That is the part to the right of the point of intersection, so x is greater than 2 1/3.

+ Think about this and write down your answer.

+ In 20 seconds teh answer follows.

Solution for c:

+ The emphasis is on the word 'open'!

+ Think about this.

+ In 30 seconds I will ask one of you.

Solution for d:

+ use the graph again

+ mind the sign for

    'greater than or equal to'!

+ key in your answer in the next slide.

answers:
A. x is greater then 2 1/3 B. x is smaller than 2 1/3
C. x is smaller than or equal to 2 1/3 D. x is greater than or equal to 2 1/3

1. A
2. B
3. C
4. D

Solution:

+ choose between line 1 and 2.

+ write down your answer and

+ compare it to the next slide,

   that includes the answer.

Solution for f:

Explanation: The arrow points to the left in number line 2.

That's good, because x is smaller than or equal to 2  1/3!

My compliments!

You've put in a lot of effort in all the questions.

By doing exercise 7 completely, 

you will have less trouble, doing §11.2 !

Now there follows ...

+       2 Theory slides, summarising what you learned and

+      one example of a homework exercise

Below is explained how to write down INTERVALS:

1st with 1 endpoint    2nd with 2 endpoints: a. 2 parts  or b. only 1 part.

The examples below explain better, I guess!

With this question  we are asked:

for which x-values does the parabola lie higher than the

straight line (or at the same height)!

For x = 2 and also for x = 5  both lie at the same height.

However, to the right of x =2  and to the left of x = 5 the parabola lies

lower. So the Solution is:    

Homework time

Do §11A.2   or  §11B.2   yourself now.

Hand in the slides of your work on GC(GoogleClassroom).