, polynomial,
logarithmic, exponential, trigonometric functions and their inverses etc We are
therefore blocked for finding 
( )
∫f x dx For example, it is not possible to find
e– x2
dx
∫
 by inspection since we can not find a function whose derivative is 
e– x2
298
MATHEMATICS
(iii)
When the variable of integration is denoted by a variable other than x, the integral
formulae are modified accordingly For instance
4
1
4
5
1
C
C
4
1
5
y
y dy
y
+
=
+
=
+
+
∫
7