Then
f (– x) = sin5 (– x) cos4 (– x) = – sin5 x cos4 x = – f (x), i e , f is an odd function Therefore, by P7 (ii), I = 0
INTEGRALS         345
Example 34 Evaluate 
4
2
4
4
0
sinsin
cos
x
dx
x
x
π
+
∫
Solution Let I = 
4
2
4
4
0
sinsin
cos
x
dx
x
x
π
+
∫