1TTO §8.5 Powers of negative numbers PTI

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

To understand §8.5 better, we first shortly look back.

Powers are explained in a basic way, there.

Task 1:

Key in your answer in the next slide!

Who's right?
Paulo says: 9
Sabine says: -9

1. Paulo: Sabine
2. both
3. Paulo
4. neither

explanation:

Task 2:

-           = 25    (A)

-           = - 25   (B)

-           = 10     ( C )

-           = - 10     (D)    Fill in the good answer in the next slide.

5​2​​

5​2​​

5​2​​

5​2​​

minus five squared equals ......

−5​2​​

1. 25
2. - 25
3. 10
4. - 10

explanation:

-         =    -  5 x 5 = - 25

So the key to the answer is that only 5 is squared, but not

the minus sign!!

5​2​​

A popular type of question now:

a Fotovraag!

Take your pen, pencil and eraser out of your pencil case and 

open your Notebook, please.

Task 3:

1. 

2. Take a picture and send it in in the next side!

3. This is a task for ALL of you.

Task 3.
everybody's Calculations:

Solution task 3:

-10 x               = 

-10 x( -8 x -8) 

= -10 x       64 = -640

(−8)​2​​

After all this squaring ......

+ we'll deal with higher powers too!

Task 4:

=  .....

Fill in your answer in the next slide, again.

(−4)​3​​

task 4:

1. 64
2. -64
3. -12
4. 12

Explanation Task 4:

=  -4 x -4 x -4 = -64

(−4)​3​​

Task 5: 

in the same way do:

=  ............

−4​3​​

Task 5:

1. -64
2. -12
3. 12
4. 64

Explanation Task 5: 

=        -   4 x 4 x 4 = -64

So, do               and             

give the same outcome?!

Indeed, they do!!        

−4​3​​

(−4)​3​​

−4​3​​

TASK 6:

one more Fotovraag!

MAKE THIS ONE IN YOUR NOTEBOOK

TAKE A PICTURE AND SEND IT IN IN NEXT SLIDE

MAKE YOUR TEACHER PROUD AND YOURSELF TOO!

TASK 6:

EXPLANATION TASK 6:

HOMEWORK TIME

Now make §9.5:

exercises   43  t/m  47.

One final remark about 46 and 47 in next slide.

As you can see, for 46 and 47 the CALCULATIONS are of the greatest importance!

So, when making them, don't just give the answers but show 

all the steps it takes, to get the answer!

Time for homework