Question

sinx+sin2x=cosx+2cos^2x

Answer 1

$sinx+sin2x=cosx+2cos^2x\ sinx+2sinx*cosx=cosx+2cos^2x\ sinx(2cosx+1)=cosx(2cosx+1)\ (2cosx+1)(sinx-cosx)=0\ 2cosx+1=0\ sinx=cosx\ \ cosx=-0.5\ tgx=1\ \ x=+-frac{2pi}{3}+2pi*n\ x=frac{pi}{4}+pi*n$