- $ F\\\left( x \\\right) = - \\\frac{1}{2}\\\cos 2x + C.$
- $ F\\\left( x \\\right) = \\\cos 2x + C.$
- $ F\\\left( x \\\right) = - \\\cos 2x + C.$
- $ F\\\left( x \\\right) = \\\frac{1}{2}\\\cos 2x + C.$