Using long division, we find that
So the asymptotes are and
This is a hyperbola with centre , asymptotes are , and vertices and .
is a graph with asymptotes and .
Use GC to plot.
Subst (2) to (1),
From graph, we observe two intersections. Thus, two roots.
As , and , the sum of series tends to , a constant. Thus, series is convergent.
Replace by . Then we have