Suppose f is a periodic function of period 2pi and that g is a horizontal shift of f, say
g(x) = f(x + a). Show that f and g have the same energy.
The Attempt at a Solution
i can see that if f(x) is shifted by 'a' that it does not make the function any difference.
but in not sure how should i go about showing it.
could someone help me out pls.