[tex]3^x+\frac{1}{3^x}=\frac{4\sqrt3}{3} \\
\\
\boxed{y=3^x} \\
\\
y+\frac{1}{y}=\frac{4\sqrt3}{3} \\
\\
3y^2+3-4\sqrt3 y=0 \\
\\
S=\{\sqrt3,\frac{\sqrt3}{3} \} \\
\\
\boxed{3^x=\sqrt3 \rightarrow 3^x=3^{\frac{1}{2}}\rightarrow x=\frac{1}{2}} \\
\\
\boxed{3^x=\frac{3^{\frac{1}{2}}}{3^1}\rightarrow 3^x=3^{-\frac{1}{2}} \rightarrow x=-\frac{1}{2}} \\
\\
[/tex]
Faltou o produto:
[tex]\boxed{\frac{1}{2}.(-\frac{1}{2})=-\frac{1}{4}}[/tex]