2TTO §1.4 Making linear formulas PTI 24-25

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 2

§1.4 Making linear formulas

Goal of this paragraph:

How to make a formula for a line that describes a relation between x and y.

1st           a freshen up:

The formula for a straight line is called a LINEAR FORMULA.

The graph for the formula s = 15 - 3a is a straight line.

This is taken from §1.1 Linear relations.

Next slide shows you the graph too!

www.desmos

video

2nd:         we make an example of a linear formula:

-  Suppose we, as a class and a teacher, go on a rowing trip on the 

    Ijsselmeer.

-  The fixed amount (the money we have to pay, no matter how many boats are hired) is 15 euros.

-  The number of boats we hire, we call b. (DON'T USE CAPITALS!!)

-  Every boat costs 5 euros.

-  The total cost for the trip we call c.

-  In the next slide CHOOSE the RIGHT FORMULA for this trip.

The right formula is:

- The fixed amount (the money we have to pay, no matter how many boats are hired) is 15 euros.

- The number of boats we hire, we call b. (DON'T USE CAPITALS!!)

- Every boat costs 5 euros.

- The total cost for the trip we call c.

1. c = 15b + 5
2. 15 + 5b = c
3. c = 15 + 5b
4. b = 15c + 5

The right answers were:

B        15 + 5b = c    or

C         c = 15 + 5b

he fixed amount (the money we have to pay, no matter how many boats are hired) is 15 euros.- The number of boats we hire we call b.

- Every boat costs 5 euros. - The total cost for the trip we call c.

3rd:   Now we have a graph given of a straight line.

How to make a linear formula?   Next slide shows you how!            

> make table

> choose starting value

> decide the gradient 

> use general formula...

     y = ax + b 

The next slide shows you

The next slide describes which steps were taken.

This is what has been done:

 15.06.28

Homework:

Evaluation