Chapter 1 - Functions and Limits - 1.1 Four Ways to Represent a Function - 1.1 Exercises - Page 22: 58

$P=2l+32/l$ Domain: $l>0$

We know that the area of the rectangle is $16\ m^2$, so: $lw=16$ The perimeter of the rectangle is: $P=2l+2w$ We need the perimeter as a function of only one side, so we eliminate $w$: $w=16/l$ $P=2l+2(16/l)=2l+32/l$ The domain is $l>0$, since the length must be positive and non-zero.