[tex]If\ is\ y=\dfrac{1}{3}x,\ then\ it's\ a\ linear\ function.\ Domain\ is\ the\ set\ of\ all\ real\ numbers.\\\\D=\mathbb{R}\\\\If\ is\ y=\dfrac{1}{3x},\ then\ domain\ is\ the\ set\ of\ all\ real\ number\ except\ 0\\\\D=\mathbb{R}-\{0\}\to x\in(-\infty,\ 0)\ \cup\ (0,\ \infty)[/tex]
