r^2 = 1 + 2\cos{\theta} + \cos^2{\theta}, \frac{dr}{d\theta} = -\sin{\theta}
I = \int_0^{2 \pi}{\sqrt{2 + 2\cos{x}}}dx
I = \sqrt{2} \int_0^{2 \pi}{\sqrt{1 + \cos{x}}}dx
I = \sqrt{2} \int_0^{2 \pi}{\frac{\sin{x}}{\sqrt{1 - \cos{x}}}}dx
I = 2\sqrt{2} [-\sqrt{1- \cos{x}}]_0^{2 \pi}
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