Step-by-step explanation:
5)
sin2a=2sina.cosa
Subtitute values in formula:
sin2a=2(3/8)(5/8)
sin2a=30/64
6)
cos2∅=2cos²∅-1
=2(5/3)²-1
=2(25/9)-1
=50/9-1
=50-9/9
=41/9
