Trigonometry

Question 2

What is the Unit Circle?

Answer 2

A circle with radius = 1 centered at (0,0).
Each point on it is (cos θ, sin θ).

Question 3

What does (cos θ, sin θ) mean?

Answer 3

x-value = cos θ
y-value = sin θ

Question 4

Signs of sin & cos in each quadrant

Answer 4

Quadrant 1: sin +, cos +
Quadrant 2: sin +, cos -
Quadrant 3: sin -, cos -
Quadrant 4: sin -, cos +

Question 5

Degrees —> Radians

Answer 5

— Q1
0° = 0
30° = π/6
45° = π/4
60° = π/3
90° = π/2
— Q2
120 = 2π/3
135 = 3π/4
150 = 5π/6
180 = π
— Q3
210 = 7π/6
225 = 5π/4
240 = 4π/3
270 = 3π/2
— Q4
300 = 5π/3
315 = 7π/4
330 = 11π/6

Question 6

Degree to Radians

Answer 6

x • π / 180

Question 7

Radians to Degrees

Answer 7

x • 180 / π

Question 8

Special Right Triangle (30-60-90)

Answer 8

ratio:

1 √3 2

“ang katapat ng 30 angle ay kalahati ng hypotenuse”
“katapat ng 60 ay √3”

Question 9

Special Right Triangle (45-45-90)

Answer 9

1 1 √2

sin 45 = cos 45
tan 45 = 1

Question 10

sin & cos

Answer 10

always < 1

Question 11

cosecant & secant

Answer 11

are always > 1

Question 12

tangent & cotangent

Answer 12

can be < 1, > 1, or = 1