f
(
x
)
=
32
1029
x
3
−
16
35
x
2
+
2
x
,
D
=
[
1
,
9
]
Area
=
∫
9
1
f
(
x
)
d
x
=
34416
1715
≈
20.0676
Riemann approximation
≈
19.9681
Number of slices: