how to consider the plane curve?

x(θ) = r(θ − sin(θ)), y(θ) = r(1 − cos(θ)), 0 ≤ θ ≤ π.

(a) What are the coordinates of the point for θ = π/2? Find the cosine of the angle between the position vector and the tangent vector at this point.

(b) Write down the parametric equations of the tangent line at θ = π/2.

(c) Find the arc length of the curve.

[Adam]

Why are you just pasting homework questions into a Matlab forum? You haven't asked a question of your own that shows you have done any work on it yourself.