[Tohn]

อีกวิธีนะคับ
$\because (x^2)^{636}=(-\frac{1}{x^2})^{636}$
$x^{1272}=\frac{1}{x^{1272}}$
$(x^{1272}-\frac{1}{x^{1272}})^2=0$
$\therefore x^{2544}+\frac{1}{x^{2544}}=2$