(3)
342
MATHEMATICS
Adding (2) and (3), we get 
( )
( )
F( ) – F( )
( )
c
b
b
a
c
a
f x dx
f x dx
b
a
f x dx
+
=
=
∫
∫
∫
This proves the property P2 Proof of P3  Let t = a + b – x Then dt = – dx When x = a, t = b and when x = b, t = a