Polar Coordinates (r,θ) Polar Coordinates (r,θ) in the plane are described by r = distance from the origin and θ ∈ 0,2π) is the counterclockwise angle1 sinθ= cos(π/2θ) 2 cosθ= sin(π/2θ) 3 tanθ= cot(π/2θ) 4 cotθ= tan(π/2θ) 5 secθ= csc(π/2θ) 6 cscθ= sec(π/2θ) =cos π/4 ∵ cos(2nπθ)= cosθ , n ∈ N =1/√2 (xiv) sin (151π/6) Solution sin (151π/6) = sin (25ππ/6)
Using Trig Angle Addition Identities Manipulating Expressions Video Khan Academy
