Mathematics WAEC / WASSCE 2006 Algebra
(a) Copy and complete the table of the relation \(y = 2\sin x - \cos 2x\). x 0^\circ 30^\circ 60^\circ 90^\circ 120^\circ 150^\circ 180^\circ y 0.5 -1.0 Using a scale of 2 cm to 30^\circ on the x- axis and 2 cm to 0.5 unit on the y- axis, draw the graph of \(y = 2\sin x - \cos 2x\), for \(0^\circ \leq x \leq 180^\circ\). (b) Using the same axes, draw the graph of \(y = 1.25\). (c) Use your graphs to find the : (i) values of x for which \(2\sin x - \cos 2x = 0\) ; (ii) the roots of the equation \(2\sin x - \cos 2x = 1.25\).