f
u
n
c
t
i
o
n
-
2
x
m
a
g
n
i
f
y
i
n
g
t
o
o
l
s
u
b
i
n
t
e
r
v
a
l
s
4
m
e
t
h
o
d
l
e
f
t
s
u
m
r
i
g
h
t
s
u
m
m
i
d
p
o
i
n
t
t
r
a
p
e
z
o
i
d
S
i
m
p
s
o
n
2
∫
0
-
2
x
d
x
a
p
p
r
o
x
i
m
a
t
e
a
r
e
a
=
0
.
2
8
5
6
6
e
x
a
c
t
a
r
e
a
=
0
.
4
9
0
8
4
|
e
r
r
o
r
|
=
2
.
0
5
×
-
1
1
0