- $ \\\int f (x){\\\mkern 1mu} {\\\text{d}}x = \\\frac{{{x^2}}}{2} + \\\cos 2x + C$.
- $ \\\int f (x){\\\mkern 1mu} {\\\text{d}}x = \\\frac{{{x^2}}}{2} + \\\frac{1}{2}\\\cos 2x + C$.
- $ \\\int f (x){\\\mkern 1mu} {\\\text{d}}x = {x^2} + \\\frac{1}{2}\\\cos 2x + C$.
- $ \\\int f (x){\\\mkern 1mu} {\\\text{d}}x = \\\frac{{{x^2}}}{2} - \\\frac{1}{2}\\\cos 2x + C$.