We prove that if
|
a
1
|
is large and
|
a
0
|
is small enough, then
every approximate zero of power series equation
P
∞
n
=0
a
n
x
n
= 0 can be
approximated by a true zero within a good error bound. Furthe
r, we
obtain Hyers-Ulam stability of zeros of the polynomial equa
tion of degree
n
,
a
n
z
n
+
a
n
−
1
z
n
−
1
+
· ··
+
a
1
z
+
a
0
= 0 for a given integer
n >
1