Question

if sin a=1/2 fhen find the value of 3 sin A-4sin³a

Answer 1

3(1/2)-4(1/2)^3
3/2-4/8
3/2-1/2
2/2
1

Answer 2

given sin a=1/2
then 3sina-4sin^3a=sin3a;i.e    sina=1/2 ;then,a=30 degrees
sin^3a=sin3(30)=sin90 degrees=1....