"(sin x+cos x)la a 2a minus sin 2x egal cu 1"
(sinx + cosx)^2 - sin2x = 1
[tex]\it (sinx + cosx)^2 - sin2x = 1 \Leftrightarrow sin^2x+2sinxcosx+cos^2x-sin2x=1\Leftrightarrow\\ \\ \Leftrightarrow sin^2x+cos^2x+sin2x-sin2x=1 \Leftrightarrow 1=1\ (Adev\breve{a}rat)[/tex]