(a) Show that the equation

\(5 \cos \theta - \sin \theta \tan \theta + 1 = 0\)

may be expressed in the form \(a \cos^2 \theta + b \cos \theta + c = 0\), where \(a, b\) and \(c\) are constants to be found.

(b) Hence solve the equation \(5 \cos \theta - \sin \theta \tan \theta + 1 = 0\) for \(0 < \theta < 2\pi\).