9709 P31 - Nov 2010 - Q4
1891
(i) By sketching suitable graphs, show that the equation \(4x^2 - 1 = \cot x\) has only one root in the interval \(0 < x < \frac{1}{2}\pi\).
(ii) Verify by calculation that this root lies between 0.6 and 1.
(iii) Use the iterative formula \(x_{n+1} = \frac{1}{2}\sqrt{1 + \cot x_n}\) to determine the root correct to 2 decimal places. Give the result of each iteration to 4 decimal places.
