θ=0°
0°
sin θ = opp side (高)
cos θ = adj side (長)
radius (半徑) = 1
180-θ
sin(0°)
θ
sin(0°)
180+θ
sin(0°)
360-θ
sin(0°)
coordinate-system
MathsIsFun
180-θ
cos(0°)
θ
cos(0°)
180+θ
cos(0°)
360-θ
cos(0°)