A question from Stein's book, Singular Integral. Let $\left\{ f_{m}\right\} $ be a sequence of integrable function such that $\int_{% \mathbb{R}^{d}}\left\vert f_{m}\left( y\right) \right\vert dy=1$ and its support converge to the origin: $\text{supp} \left( f\right) =cl\left\{ x:f_{m}\left( x\right) \neq 0\right\} $ In this text, by simple limiting argument we get $\displaystyle \lim_{m\rightarrow \infty }\int_{\mathbb{R}^{d}}\frac{f_{m}\left( y\right) }{\left\vert x-y\right\vert ^{d-\alpha }}dy= \frac{1}{\left\vert x\right\vert ^{d-\alpha }}. $
Could you explain me how to get the above result?