BigGUN написа:(√(2+√3) )^x+(√(2-√3) )^x=2^x help
[tex](\sqrt{2+\sqrt{3}})^x+(\sqrt{2-\sqrt{3}})^x=2^x[/tex]
Забелязваме, че:
[tex](\sqrt{2+\sqrt{3}}).(\sqrt{2-\sqrt{3}})=\sqrt{(2+\sqrt{3}).(2-\sqrt{3})}=\sqrt{2^2-(\sqrt{3})^2}=\sqrt{4-3}=\sqrt{1}=1=>[/tex]
[tex]\sqrt{2-\sqrt{3}}=\frac{1}{(\sqrt{2+\sqrt{3}})[/tex]
[tex](\sqrt{2+\sqrt{3}})^x+(\frac{1}{\sqrt{2+\sqrt{3}}})^x=2^x[/tex]
[tex](\sqrt{2+\sqrt{3}})^x+\frac{1^x}{(\sqrt{2+\sqrt{3}})^x}=2^x[/tex]
[tex](\sqrt{2+\sqrt{3}})^x+\frac{1}{(\sqrt{2+\sqrt{3}})^x}=2^x |:2^x \ne 0[/tex]
[tex]\frac{(\sqrt{2+\sqrt{3}})^x}{2^x}+\frac{1}{\frac{(\sqrt{2+\sqrt{3}})^x}{2^x}}=\frac{2^x}{2^x}[/tex]
[tex](\frac{\sqrt{2+\sqrt{3}}}{2})^x+\frac{1}{(\frac{\sqrt{2+\sqrt{3}}}{2})^x}=1[/tex]
пол: [tex](\frac{\sqrt{2+\sqrt{3}}}{2})^x=y, y>0[/tex]
[tex]y+\frac{1}{y}-1=0...[/tex]