Let sin alpha 45 and 0 Solution1 sinalphabeta sin alpha 45

Solution

1. sin(alpha-beta)

sin alpha= 4/5

cos alpha=3/5

cos beta= 5/13

sin beta=12/13

sin(alpha - beta)= sin alpha cos beta-cos alpha sin beta= (4/5)(5/13)-(3/5)(12/13)= -16/ 65

correct option is c

2. cos(-30)= cos 30=sqrt3/2

Correct option is d