2
(
) (
) (
)
px
qx
r
x
a
x
b
x
c
+
+
−
−
−
=
A
B
C
x
a
x
b
x
c
+
+
−
−
−
4 2
2
(
) (
)
px
qx
r
x
a
x
b
+
+
−
−
=
2
A
B
C
(
)
x
a
x
b
x
a
+
+
−
−
−
5 2
2
(
) (
)
px
qx
r
x
a
x
bx
c
+
+
−
+
+
=
2
A
B + C
x
x
a
x
bx
c
+
−
+
+
where x2 + bx + c can not be factorised further � Integration by substitution
A change in the variable of integration often reduces an integral to one of the
fundamental integrals