The function f is definited in $\Bbb R^d$ by $$f(x)=\frac{1}{(|x|^\frac{d}{2}+|x|^d)}$$
How do you find $p\in[0.+\infty]$ such that $f(x)\in L^p$ ?
Any help is appreciated.
My attempt:
$r=|x| $, $r\in \Bbb R_+^d$:
$$||f||_p^p=\int_0^{+\infty} \frac{dr}{r^\frac{dp}{2}(1+ r^\frac{d}{2})^p}$$
In the neighbourhood of $x=0$: $\frac{dp}{2}<1$
In the neighbourhood of $x=+\infty$ : $p>1$.