Răspuns:
notez sqrt = radical
8. sin2x=2sinx*cosx
cosx = sqrt(1-sin^2x)=sqrt(1-9/25)=sqrt(16/25)=4/5
Deci sin2x=2*3/5*4/5=24/25
9. Rezolvam determinantul si obtinem [tex]x^{4} -(x-1)^{2} *(x-1)^{2} =x^{4}-x^{4}-2x^{3}-x^{2}+2x^{3} +4x^{2} +2x-x^{2} -2x-1[/tex]
dupa simplificare [tex]2x^{2} -1[/tex]=0
si avem [tex]x^{2} =\frac{1}{2} \\x=+-\frac{\sqrt[2]{2} }{2}[/tex]
Explicație pas cu pas:
