Convolution - prove commutative

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anyone know how to prove that it is commutative...

as if f *g = g*f
 
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Try a change of variables.
 
You might want to start with the definition: the convolution of f and g is
f*g(x)= \int_0^\infty f(x-t)g(t)dt and, of course, g*f(x)= \int_0^\infty g(x-u)f(u)du (I have intentionally used a different variable of integration here). Hmm, in one you have f(x-t) and in the other f(u). Does that substitution benndamann33 mentioned leap to mind?
 

Thread 'Finding the nth roots of a complex number'

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