1. r y x

2. What do you remember about this triangle?
And this one? c b r y x a

3. r y c x b a

4. θ And r can be found by… The terminal side of the angle here is r r
(1, 2) r θ
Starting θ from the positive x-axis is called Standard Position

5. ? θ And r can be found by… The terminal side of the angle here is r r
(1, 2)
Important Note: the value of r will always be positive r y ? θ x

6. (1, 2) r θ

7. So the general formulas look like this:
(x, y) r θ

8. The acute angle made between the terminal side (r)
Here θ is the reference angle
This is the same θ we saw in the first quadrant
reference angle
(–1, 2)
The acute angle made between the terminal side (r) r
and the x-axis θ

9. Find all of the trig functions of α
(–1, 2) r θ
Compare these with our QI angle

10. (1, 2) r θ
Same trig values only the cosine and secant are negative in the QII case

11. Find all of the trig functions of α
(–1, 2) r θ

12. Co-terminal angles
Angles that have the same initial and terminal sides
(–1, 2)
α and β are examples of co-terminal angles. r β
Co-terminal angles always differ by multiples of 360°
Left off here
They also will have the same sine, cosine, tangent, etc.

13. Find all of the trig functions of α given a terminal side through the point (9, 40)
----- Meeting Notes (9/19/11 09:14) -----
Change symbols; remember that from pc to mac some symbols are blocked

14. Find all of the trig functions of α given a terminal side through the point (–5, –12)
----- Meeting Notes (9/19/11 09:14) -----
Change symbols; remember that from pc to mac some symbols are blocked

15. Find all of the trig functions of θ given that
…and θ is in Quadrant IV
But since we’re in Quadrant IV