Question 868053
{{{8cos^2(x)-4=0}}}
{{{cos^2(x)-1/2=0}}}
{{{(cos(x)-1/sqrt(2))(cos(x)+1/sqrt(2))=0}}}
{{{(cos(x)-sqrt(2)/2)(cos(x)+sqrt(2)/2)=0}}}
Two solutions:
{{{cos(x)-sqrt(2)/2=0}}}
{{{cos(x)=sqrt(2)/2}}}
{{{x=pi/4}}} and {{{x=(7/4)pi}}}
and
{{{cos(x)+sqrt(2)/2=0}}}
{{{cos(x)=-sqrt(2)/2}}}
{{{x=(3/4)pi}}} and {{{x=(5/4)pi}}}