3.4: Logo of three sectors with variable radii

0606/22/F/M/24 — Question 9 · 9 marks

3.4 diagram
In this question all lengths are in centimetres and all angles are in radians.
The diagram shows a company logo. Each part of the logo is a sector of a circle with centre OO.
Sector AOBAOB has radius xx.
Sector CODCOD has radius x+2x + 2.
Sector EOFEOF has radius yy.
The shaded region has area A cm2A\text{ cm}^{2} and perimeter 2424.
It is given that xx and yy can vary.
(a)
Show that A=918x268x+132A = \dfrac{91}{8}x^{2} - 68x + 132.
[4]
(b)
Use differentiation to find the minimum possible area of the logo.
[5]