## Precalculus (6th Edition) Blitzer

There are no "negative" sheep. The position of the sheep is negative with respect to the ${{\left( n \right)}^{\text{th}}}$ sheep. Note that here $n-1$, $n$, and $n+1$ in the suffixes indicate the ${{\left( n-1 \right)}^{\text{th}}}$, ${{\left( n \right)}^{\text{th}}}$ and ${{\left( n+1 \right)}^{\text{th}}}$ sheep, and not the number of sheep. Thus the statement does not make sense.