Question

4 cos² x + sin x = 1

Answer 1

sin(x)+2cos(2x)+2=1
$-sin^{2}$(x)+sin(x)+2$cos^{2}$(x)+2=1
$frac{1}{2}$$ie^{-ix}- frac{1}{2}ie^{ix}+e^{-2ix}+e^{2ix}+2=1$
x=2($pi$n+$tan^{-1}( frac{1}{3} (-4- sqrt{7}))), n∈Z$
x=2($pi n+ tan^{-1} ( frac{1}{3}( sqrt{7}-4))), n∈Z$
x=$frac{1}{2}(4 pi n+ pi ), n∈Z$