Chapter 6 - Trigonometry

sin(θ)

Opposite/Hypotenuse

Cos(θ)

Adjacent/Hypotenuse

Tan(θ)

Opposite/Adjacent or Sin(θ)/Cos(θ)

Depression and Elevation Angle

are equal

Gradient (Hypotenuse) of a Unit Circle

1

Sin(θ) in the Unit Circle

y axis

Cos(θ) in the Unit Circle

x axis

x and y values in a unit circle are always

-1<=x and y <= 1

Quadrant 1

+sin, +cos, +tan

Quadrant 2

+sin,-cos,-tan

Quadrant 3

-sin,-cos,+tan

Quadrant 4

-sin,+cos,-tan

Reference Angle 90-180

180 - θ

Reference Angle 180-270

θ-180

Reference Angle 270-360

360-θ

sin(θ) graph

starts at 0

cos(θ) graph

starts at 1

sin(θ) 30

1/2

sin(θ) 45

square root 2/2

sin(θ) 60

square root 3/2

cos(θ) 30

square root 3/2

cos(θ) 45

square root 2/2

cos(θ) 60

1/2

tan(θ) 30

square root 3/3

tan(θ) 45

1

tan(θ) 60

square root 3