Question

(ii) Write down the number of roots of the equation 2 cos 2θ − 1 = 0 in the interval 0 ≤ θ ≤ 2π. [1]
(iii) Deduce the number of roots of the equation 2 cos 2θ − 1 = 0 in the interval 10π ≤ θ ≤ 20π

Answer 1

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Mathematics%20(9709)/9709_w11_qp_11.pdf Q3i