Aratati ca sin 2x / 1 + cos 2x = tg x . X apartine (0; pi/2).

Răspuns :


[tex]\it \dfrac{sin2x}{1+cos2x} = \dfrac{2sinxcosx}{1+2cos^2x-1} = \dfrac{2sinxcosx}{2cos^2x} = \dfrac{sinx}{cosx} =tgx[/tex]