`~rai~`
\(cot(45^o-x)=\dfrac{\sqrt{3}}{3}\\ĐKXĐ:sin(45^o-x)\ne 0\\\Leftrightarrow 45^o-x\ne k180^o\\\Leftrightarrow x\ne 45+k180^o(k\in\mathbb{Z})\\PT \Leftrightarrow cot(45^o-x)=cot60^o\\\Leftrightarrow 45^o-x=60^o+k180^o\\\Leftrightarrow x=-15^o+k180^o.(k\in \mathbb{Z})\)
$# Băng Cướp Cầu Vồng.$