2Tvwo §9.4 Solving inequalities (2)

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 2

§9.4 Solving inequalities

(ongelijkheden)

Up to now we only dealt with equations, so:                  

              'something being equal to something else'.

However,  

something could also be greater than or smaller than                                      something else!

Below you see what you will learn and the kind of tasks 

you are going to solve. But how?! 

Do you remember the signs:

           for 'smaller than'       and 

           for 'greater than'?

A balance or a graph...

Next slide ....

Shows the MEANING of the process of solving an equation.

You get a good idea for what situations it could be used.

Only after that we will watch every little step!

As you can see in the graphs,

for 30 minutes the water level is the same in A and B.

Task 'e' asks us for which VALUES (so more than one!) of t graph A is HIGHER then graph B

                 

Finally here comes the METHOD how to 

SOLVE an INEQUALITY (ongelijkheid).

SOLVING INEQUALITIES:

We don't have graphs (yet), but just an INEQUALITY!

In order to SOLVE this, 

we will make a SKETCH of the two graphs ourselves.

Next slides show how to do all this!

The following slide shows you an example of this METHOD!

Practicing solving inequalities!

Now you get a complete example from me to watch and try to understand.

After all this it will be much easier for you to do §9.4 Solving inequalities!

Let's do c now.

step 1: make an equation:

step 2: solve this equation:

step 3: sketch the 2 graphs:

                                                           Extra (not really needed): 

step 4: Read off the solution from the inequality:

Solution:

After all is said and done ...

There are exercises 29, 30 and 31 to be done by yourself.

In 29 and 30 no graphs are given, so just 

+ work out the 4 points from the Method on p.102, we just went through

+ making sketches of both graphs, etc.

Homework time

DO:

§9.4:      29, 30 and 31

CHECK your WORK with the SOLUTIONS BOOK and

SEND in a few PICS in GC

Looking forward to your work!