Question 401382
{{{(cos(2x))^2+4(sinx)^2*(cosx)^2=1}}}
{{{(cos(2x))^2+(2*sinx*cosx)^2=1}}}
Use FORMULA {{{2*sinx*cosx=sin(2x)}}}
{{{(cos(2x))^2+(sin(2x))^2=1}}}
Use FORMULA {{{(sinx)^2+(cosx)^2=1}}}, so  {{{(sin(2x))^2+(cos(2x))^2=1}}}
{{{1=1}}}