# ISI2015-MMA-76

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Given that $\int_{-\infty}^{\infty} e^{-x^2} dx = \sqrt{\pi}$, the value of $$\int_{-\infty}^{\infty} \int_{-\infty}^{\infty} e^{-(x^2+xy+y^2)} dxdy$$ is

1. $\sqrt{\pi/3}$
2. $\pi/\sqrt{3}$
3. $\sqrt{2 \pi/3}$
4. $2 \pi / \sqrt{3}$
in Calculus
recategorized

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