9709 P31 - Jun 2020 - Q6
1873
The diagram shows a circle with centre O and radius r. The tangents to the circle at the points A and B meet at T, and angle AOB is 2x radians. The shaded region is bounded by the tangents AT and BT, and by the minor arc AB. The area of the shaded region is equal to the area of the circle.
(a) Show that x satisfies the equation \(\tan x = \pi + x\).
(b) This equation has one root in the interval \(0 < x < \frac{1}{2}\pi\). Verify by calculation that this root lies between 1 and 1.4.
(c) Use the iterative formula \(x_{n+1} = \arctan(\pi + x_n)\) to determine the root correct to 2 decimal places. Give the result of each iteration to 4 decimal places.
