Question 1027900
{{{(1-cos^2(x))-cos^2(x)=cos(x)}}}


{{{1-2cos^2(x)-cos(x)=0}}}


{{{2cos^2(x)+cos(x)-1=0}}}


{{{cos(x)=(-1+- sqrt(1-4*2*(-1)))/(2*2)}}}


{{{cos(x)=(-1+- sqrt(9))/4}}}


{{{cos(x)=(-1+- 3)/4}}}


{{{system(cos(x)=-1,OR,cos(x)=1/2)}}}


{{{system(x=180,OR,x=60,OR,x=300)}}}------degrees