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10 votes
1 answer
833 views

This is not a dyadic cosine-product

The double-angle formula, $\sin2x=2\sin x\cos x$, turns the scary-looking integral $$\int_0^{\infty}dz\prod_{k=1}^{\infty}\cos\frac{z}{2^k}$$ into fun once you realize $\prod_k\cos\frac{z}{2^k}=\frac{\...
T. Amdeberhan's user avatar
0 votes
1 answer
171 views

How to compute $\int_{-\infty}^{\infty}\int_{-\infty}^{\infty}\int_{[-1,1]^n}\exp[2\pi i(\theta_1 v_1.x+\theta_2v_2.x)]d^nx d\theta_1d\theta_2$

Let $\mathbf{v}_1, \mathbf{v}_2$ be two vectors in $\mathbb{R}^n$. I would like to compute the following singular integral: $$\int_{-\infty}^{ \infty} \int_{-\infty}^{\infty} \int_{[-1,1]^n} e(\...
Johnny T.'s user avatar
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