Consider the parametric equations x(θ)=sinθ+θ and y(θ)=cosθ−θ for 0<θ<2π.
a. Determine all values of θ in the interval (0,2π) where the tangent line to the curve is horizontal. Show all supporting work.
b. At θ=3π, compute the slope of the curve and decide whether the curve is increasing or decreasing with respect to x at that point. Clearly explain each step of your reasoning.