1) These are just a matter of actually using the identity given. Very little thinking needed. Just look at the numbers in place of 'A' and 'B' in the given identity, and then it's literally a matter of copying the corresponding numbers of A and B.
a) A=6, B=4..
=> INT sin(6+4)x + sin(6-4)x dx
= INT sin10x + sin2x dx
= (-1/10)cos10x - (1/2)cos2x + c
Exactly the same method for b)