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Rezolvati ecuatia: [tex]2(cosx-sinx) = \frac{1}{sinx + cosx}....... x, apartine, [0;\frac{\pi}{2}] [/tex]

Răspuns :

[tex]2(cosx-sinx)= \frac{1}{sinx+cosx},[/tex], x∈[0; π/2]. Inmultim egalitatea cu sinx+cosx ⇒
[tex]2(cos^2x-sin^2x)=1,sau.cos2x= \frac{1}{2},deci. [/tex] 2x=π/3 ⇒x=π/6.