The curvature at a point P of a parametric curve x = x(t), y = y(t) is given below, where the dots indicate derivatives with respect to t, so ẋ = dx/dt. Use the formula to find the curvature of the cycloid x = θ − sin(θ), y = 1 − cos(θ) at the top of one of its arches. $ \kappa = \dfrac {\left| \dot{x} \ddot{y} - \ddot{x} \dot{y} \right|} {[\dot{x}^2 + \dot{y}^2]^{3/2}} $