## Calculus 10th Edition

First, find the derivative using the power rule, $((x^n)'=nx^{n-1})$ to get $y'=-\frac{2}{x^3}$ Horizontal tangent$\rightarrow y'=0\rightarrow -\frac{2}{x^3}=0 \rightarrow -2=0$ which is not true hence no solution. Therefore the derivative is never $0$ and hence there are no horizontal tangents.