Question

cos(x+50°)+sin(x+40°)=1+2cosx sin 40°+cos 90 x

Answer 1

$cos(x+50)+sin(x+40)=1+2cosxsin40+cos90\\\\cosxcos50-sinxsin50+sinxcos40+cosxsin40=1+2cosxsin40+\\+cos90\\\\cosxcos(90-40)-sinxsin(90-40)+sinxcos40+cosxsin40=\\=1+2cosxsin40+cos90\\\\cosxsin40-sinxcos40+sinxcos40+cosxsin40=1+2cosxsin40+0\\\\2cosxsin40=1+2cosxsin40\\0=1$
Решений нет.