3THavo § 7.3 Fractional formulas

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§ 7.3 Fractional formulas

First we shortly look back at 

+  § 7.1   and

+  § 7.2

Question 1

Calculate y = -3p²   for p = -4

For all questions do as follows:

+ Work it out on scrap paper and

+ Show your answer on the Mini White Board

+ Only when I say so, not earlier!

Answer 1

y = -3p²  for  p = -4

y = -3 x (-4)² = -3 x 16 = -48

Question 2

Find out on your scrap paper, 

if there is a quadratic relation in this table:

Answer 2

Question 3

1. Are x and y directly proportional?

2. If so, what is the constant of proportionality?

3. Make the formula for this table.

Answer 3

1.        Yes, because if you do x times a certain number, then

            y is multiplied by that same number.

2.        The constant of proportionality is 3.

3.         y = 3x

Question 4

1. Is this table inverse proportional?

2. If so, make the formula.

Answer 4

1. Yes!

2.  There are 3 possibilities:

a.        x times y = 100   (I write 'times' to distinguish from letter x)

b.        y = 100/x    or

c.      x = 100/y

Time for § 7.3 = Homework

Fractional formulas, it is about.

You will notice that the variables in these formulas have an

'inversely proportional' relation. 

Later we will get back at this LessonUp for a little while.

So you can use what you've learnt in § 7.2!

Good luck!

4T Ch 7 on

Friday 31st of January 

Theory on Fractional formulas:

See next slide!

More Theory 

See next slide!

Good luck, doing most of § 7.3.

What did you learn this lesson?