(a) A filamentary loop carrying current I is bent to assume the shape of a regular polygon of n sides. Show that at the center of the polygon where r is the radius of the circle circumscribed by the polygon.(b) Apply this to cases when n = 3 and n = 4 and see if your results agree with those for the triangular loop of Problem 7.8 and the square loop of Problem 7.10, respectively.(c) As n becomes large, show that the result of part (a) becomes that of the circular loop of Example7.3.

nl sin 2ar