Two curves are given by y1=sinx+x and y2=xtanx for 0<x<2π.
a. (i) Find the expressions for the slopes of the tangents to y1 and y2 at any point x in the stated interval.
b. (ii) Show that the tangents to the two curves are parallel when sinx=xsec2x−1 and hence find the common x–coordinate of such points, correct to two decimal places.
c. (iii) Determine the acute angle between the two curves at x=4π.