What does this integral notation mean?

Leo Liu
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I saw it somewhere but I did't know exactly what it meant. Could someone explain it to me like I am 5? Does it mean we integrate with respect to x n times?
$$\int_{\mathbb{R}^n}f\, \mathrm{d}^n x$$
 
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Leo Liu said:
Homework Statement:: .
Relevant Equations:: .

I saw it somewhere but I did't know exactly what it meant. Could someone explain it to me like I am 5? Does it mean we integrate with respect to x twice?
$$\int_{\mathbb{R}^n}f\, \mathrm{d}^n x$$
It means ##\int_\mathbb{R}\int_\mathbb{R}\ldots\int_\mathbb{R}f \,dx_1\,dx_2\ldots\,dx_n##
 
fresh_42 said:
It means ##\int_\mathbb{R}\int_\mathbb{R}\ldots\int_\mathbb{R}f \,dx_1\,dx_2\ldots\,dx_n##
Thanks. Just need some clarification -- do x-n s represent the same parameter or different variables?
 
Leo Liu said:
Thanks. Just need some clarification -- do x-n s represent the same parameter or different variables?
Different variables. The integral is over a region in ##\mathbb R^n##. Each ##dx_i## is a different dummy variable, much the same as ##\int \int f(x, y) dx dy##.
 
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