3THavo §7.1 Quadratic formulas 1-5

• Wiskunde
• Middelbare school
• havo
• Leerjaar 3

Today's Homework is

§ 7.1 Quadratic formulas, 1-5

But first,

  See next slide!

Mistake in Solutionsbook p.208:

This is about the REFRESH:

The words 'The y-intercept'

 should

 be:

'The gradient' !    

So the question in R3, p.244  should've been

'Give the gradient',  too!   Please correct this with a pencil!        

Who discovered this mistake?

Calculate in your head:

y = x² + 6x     

^{for x = -3}       

y = .....

Explanation:

y = (-3)² _{+ 6 x -3 = 9  + -18 = -9}

_TIPS:

_{1. when you square a negative number} the outcome is positive!

_{2. Use brackets around -3 !}

We do exercise 2a together:

+ All take p.246, exercise 2a before you.

+ Who's going to read out aloud (not too loud...) the

first sentence and question a?

Fate, that is Lollipopsticks, decides!

+ Who's going to explain 2a? The oldest -and wisest?- one in class!

Time to do some Homework.

Work on § 7.1 for yourself.

Later in this lesson we will continue the LessonUp.

New stuff - the right stuff...

Get ready!

What's next?

The 'right stuff' from the last, somewhat mysterious  slide is about:

 a fine Method to find out 

+  if a Formula is about a Quadratic Relation,

+ by Investigating a Table...

Another Mistake in Solutionsbook:

                 p.211 exercise 5c:

Contrary to the book, that says there isn't,

there certainly is a Quadratic Relation between x and y.  Please:

             + correct this with a pencil and

             + try to find the calculating mistake the writer made (when you arrive                      at exercise 5c!)

TIP for doing 4, 5 (,6 and 7c)

The Method you just learnt:

finding out wether a Formula shows a Quadratic Relation or not,

USE THIS when doing 4, 5  (,6 and 7c!) 

Work on on the Homework.

What did you learn this lesson?