Andrewkirk: Yes, right, that's the one.
Ray vickson, I get the same series but still have this x=0 problem.
I still don't know what is the correct answer to this cuestion a)
b) I tried to convert it in an one-dimensional integral with polar coord.:
\int_C \delta (\vec{\alpha_0}-\vec{\alpha})...
Thx, but I don't get it! Is there a way to show this? Or at least an explanation? I know the relation ∫δ(x-a) dx= θ(x-a) but I've never seen
∫δ(g(x)-a) dx =
0 g(x) ≠a
1 g(x)=a
Homework Statement
a) ∫δ( x² cos x) dx with x from -∞ to +∞
b) Integral over C, with C = unit circle
∫C δ(α-α0) a ds
a =(1,1)
Homework Equations
a) δ(g(x)) =∑δ(x-xi)/|g'(xi)|
b)?
The Attempt at a Solution
a) g(x) = x² cosx
g'(x) = 2x cos x - x² sin x
xi = 0 and (2n+1)π/2...