(949) 305-1705 info@areteem.org
社交网络
This seems to be a typo, since the sum of the roots $r + s = 2$. So, the solution should say $$\dfrac{1}{r} + \dfrac{1}{s} = \dfrac{r + s}{rs} = \dfrac{2}{\frac{1}{2}} = 4.$$
Thanks for pointing this out!
社交网络