- $ D = \\\left( {2;4} \\\right)$
- $ D = \\\left[ {2;4} \\\right]$
- $ D = \\\left\\\{ {2;4} \\\right\\\}$
- $ D = \\\left( { - \\\infty ;2} \\\right) \\\cup \\\left( {4; + \\\infty } \\\right)$