1718 WH3X CH4 Lesson 2

• Wiskunde
• Middelbare school
• havo
• Leerjaar 3

Place your notebook on your desk and find your homework.
Which homework exercises should I discuss on the board?

Refresh

Parabolas
Calculation order
Square roots

Parabolas

The graph of a quadratic formula
is called a parabola.
If the number in front of         is negative,
the graph is an upward opening parabola,
if it is positive the graph is a downward
opening parabola.
Parabolas are symmetrical, you can draw a
vertical line that is the axis of symmetry.
The vertex (highest or lowest point of the
parabola) lies on the axis of symmetry.

What type of parabola corresponds to this formula?

y=5x−4x​2​​

1. Upward opening parabola
2. Downward opening parabola
3. It is not a parabola

Calculation order/Order of operations

When calculating, follow the order of operations:

• First calculate what is between brackets
• Then raise to a power and take the square root from inside to outside
  
• Then multiply and divide from left to right
• Then add and subtract from left to right
  

Powers and brackets

When raising a number to a power, there is a difference if the number is in brackets or not!

Calculate

−2​4​​+(3−8)​2​​=

Square roots

What is the square root of 100?

1. 10
2. 50
3. 10000
4. 200

Adding/Subtracting square roots

Write as short as possible:

3√​5​​​+7√​11​​​+5√​5​​​=

1. 8√​10​​​+7√​11​​​
2. 8√​5​​​+7√​11​​​
3. 15√​21​​​
4. something else

Multiplying square roots

Write as short as possible:

2√​11​​​⋅3√​7​​​=

1. 5√​18​​​
2. 5√​77​​​
3. 6√​18​​​
4. 6√​77​​​

Homework Monday

CH4, Refresh.
Make and correct:
R3, R6, R7, R8

Any (useful) comments on this lesson and/or the old/new homework?