Given, Â Â $$\left(x+\ \frac{\ 1}{x}\right)^2=3$$
        $$x+\ \frac{\ 1}{x}=3^{\ \frac{\ 1}{2}}$$
Hence  $$x^3+\ \frac{\ 1}{x^3}=\left(x+\ \frac{\ 1}{x}\right)^3-3.x.\ \frac{\ 1}{x}\left(x+\ \frac{\ 1}{x}\right)$$
                $$=\left(3^{\ \frac{\ 1}{2}}\right)^3-3\left(3^{\ \frac{\ 1}{2}}\right)$$
                $$= 3^{\ \frac{\ 3}{2}}-3^{\ \frac{\ 3}{2}}$$
                $$= 0$$
Create a FREE account and get: