Compute the boundary and interior of $\left \{ \left(t,\frac{1}{t}\right) : \frac{1}{4} 
Let $\mathbb{R}^2$ be given with $|\cdot |_\infty$.Compute the boundary and interior of $A=\left \{
 \left(t,\frac{1}{t}\right) : \frac{1}{4} <t <4\right \}$
I suppose that the interior of $\left \{
 \left(t,\frac{1}{t}\right) : \frac{1}{4} <t <4\right \}$ is every point that lies on $f(t)=1/t$ with $1/4<t<4$.
I'm having trouble with the boundary - can anyone help?

The interior is empty and the boundary (which is also the closure)  is $\{(t,\frac  1 t): \frac 1 4 \leq t \leq 4\}$. 
