1. The Wave Function a cosx + b sinx R cos(x±α) or R sin(x±α)
What is to be learned?
How to express
a cosx + b sinx
in the form
R cos(x±α) or R sin(x±α)

2. Graph 1 -1 1 1 -1 1 1 -1 -1 1

3. √2 1 -1
-√2

4. General Method So and Reminder 1
Quadrant 1 because cosα and sinα both positive

5. Quadrant of α according to signs of cosα and sinα

6. Page 253 no. 2
Reminder So 1
and
Quadrant 4 because cosα positive and sinα negative

7. Page 253 no. 7b) So and Minimum required working
α in Quadrant 4 because cosα positive and sinα negative
and