- $ D = \\\left( {0; + \\\infty } \\\right)$.
- $ D = \\\left[ {0; + \\\infty } \\\right)$.
- $ D = \\\left[ {\\\frac{1}{3}; + \\\infty } \\\right)$.
- $ D = \\\left( {\\\frac{1}{3}; + \\\infty } \\\right)$.