Let $x,y \in \mathbb{R}$, and $0<p<\infty$. Prove $$|x-y|^p\leq (1+2^p)(|x|^p+|y|^p) $$
The case $0<p\leq1$ is obvious, as it follows from the properties of the P-norm, where $P:=1/p$, $$|x-y|^p=|x-y|^{1/P}\leq |x|^{1/P} + |y|^{1/P} = |x|^{p} + |y|^{p} \leq (1+2^p)(|x|^p+|y|^p)$$. But I'm stumped for the case $1<p<\infty$. Could someone point me in the right direction? Hope I'm not missing something obvious.