(a) Start with the given equation:
\(\cos(x - 30^\circ) = 2 \sin(x + 30^\circ)\)
Use the angle subtraction and addition formulas:
\(\cos(x - 30^\circ) = \cos x \cos 30^\circ + \sin x \sin 30^\circ\)
\(\sin(x + 30^\circ) = \sin x \cos 30^\circ + \cos x \sin 30^\circ\)
Substitute the exact values:
\(\cos 30^\circ = \frac{\sqrt{3}}{2}, \quad \sin 30^\circ = \frac{1}{2}\)
\(\cos(x - 30^\circ) = \cos x \frac{\sqrt{3}}{2} + \sin x \frac{1}{2}\)
\(\sin(x + 30^\circ) = \sin x \frac{\sqrt{3}}{2} + \cos x \frac{1}{2}\)
Substitute into the original equation:
\(\cos x \frac{\sqrt{3}}{2} + \sin x \frac{1}{2} = 2 \left( \sin x \frac{\sqrt{3}}{2} + \cos x \frac{1}{2} \right)\)
Expand and simplify:
\(\cos x \frac{\sqrt{3}}{2} + \sin x \frac{1}{2} = \sin x \sqrt{3} + \cos x\)
Rearrange terms:
\(\cos x \frac{\sqrt{3}}{2} - \cos x = \sin x \sqrt{3} - \sin x \frac{1}{2}\)
Factor out terms:
\(\cos x \left( \frac{\sqrt{3}}{2} - 1 \right) = \sin x \left( \sqrt{3} - \frac{1}{2} \right)\)
Divide both sides by \(\cos x\) and \(\sin x\):
\(\tan x = \frac{\frac{\sqrt{3}}{2} - 1}{\sqrt{3} - \frac{1}{2}}\)
Simplify to obtain:
\(\tan x = \frac{2 - \sqrt{3}}{1 - 2\sqrt{3}}\)
(b) From part (a), we have:
\(\tan x = \frac{2 - \sqrt{3}}{1 - 2\sqrt{3}}\)
Calculate \(x\) using the inverse tangent function:
\(x = \tan^{-1}\left(\frac{2 - \sqrt{3}}{1 - 2\sqrt{3}}\right)\)
Find solutions within the interval \(0^\circ < x < 360^\circ\):
\(x \approx 173.8^\circ, 353.8^\circ\)