Question

cos2x=cosx+sinx помогите плиизз

Answer 1

$cos2x=cos x+sin x\cos^2-sin^2x=cos xsin x\(cos x-sin x)(cos x+sin x)=cos x+sin x\cos x+sin x=0\cos x=-sin x\tg x=-1\x=frac{3pi}4+pi n,;ninmathbb{Z}\cos x+sin xneq0:\cos x-sin x=0\cos x=sin x\tgx=1\x=fracpi4+pi n,;ninmathbb{Z}\OTBET:;frac{3pi}4+pi n,;frac{pi}4+pi n,;ninmathbb{Z}$

Answer 2

от души брат