$1)\pi < x < \dfrac{3\pi}{2}\\ \Rightarrow \cos x, \sin x<0\\ \tan x=\dfrac{1}{\cot x}=\dfrac{17}{8}\\ \dfrac{1}{\cos^2x}=\dfrac{\cos^2x+\sin^2x}{\cos^2x}=1+\tan^2x\\ \Rightarrow \cos x=-\sqrt{\dfrac{1}{1+\tan^2x}}=-\dfrac{8\sqrt{353}}{353}\\ \cos^2x+\sin^2x=1\\ \Rightarrow \sin x=-\sqrt{1-\cos^2x}=-\dfrac{17\sqrt{353}}{353}\\ 5)2005^o=205^o+5.360^o$
Suy ra góc cần tìm là $205^o$
