Question

Solve the equation for all values of x. Not really sure how to do this? cos x = 3*cos x - 2

Answer 1

$\bf cos(x)=3cos(x)-2\implies 0=3cos(x)-2-cos(x) \\\\\\ 0=2cos(x)-2\implies 2=2cos(x)\implies \cfrac{2}{2}=cos(x)\implies 1=cos(x) \\\\\\ cos^{-1}(1)=\measuredangle x\implies \measuredangle x= \begin{cases} 0\\ 2\pi \end{cases}$