3Tvwo §6.3 / 3Thavo §6.4

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 3

§6.3 Sine and cosine

First a look back at §6.2!

​2​​a​​

If 6 =

then a = ......

​a​​32​​

If 4 =

then a = .....

Using the tangent to calculate the angle of elevation.

+ Take an empty space in your notebook and first

+ Make a Sketch of this:

The Sketch:

Now calculate:

+ the angle of elevation

+ using         a. your Sketch  and 

                         b. your calculator

Solution:

Difference between a tangent and an angle.

1. there is none, in fact
2. a tangent is about steepness; an angle is not
3. an angle is in degrees; a tangent is a number
4. an angle is a number; a tangent is in degrees

you use 'shift tan' on the Casio, when you

1. know the angle and you want to know the tangent.
2. know 2 sides of a right-angled triangle and you want to calculate the 3rd side.
3. know the tangent and you want to know the angle.
4. want to round an angle to a whole number of degrees.

Homework time.

Do §6.3 now.

Later this LessonUp will be continued.

What's new in §6.3 ?

A lot!

The reason for this: sometimes it is better to use:

SINE or COSINE than TANGENT!

Just watch the next slide!

You will also see a way to remember all three of them!

Three more things...

1.       Which angle is meant?

2.      A mistake in the book!

3.       A joke (or two).

1.   Which angle do you mean?!?

2.  Mistake in the book, p.201:

16d, 'Angle S' should be 'Angle P'!

Correct this, with a pencil.

Homework time again.

Try to finish the paragraph.