θ=0°

0°

sin θ = opp side (高) ÷ r

cos θ = adj side (長) ÷ r

radius (半徑) = 1

180-θ sin(0°)	θ sin(0°)
180+θ sin(0°)	360-θ sin(0°)

180-θ cos(0°)	θ cos(0°)
180+θ cos(0°)	360-θ cos(0°)

coordinate-system MathsIsFun