Find sin(2A) if sin(A) = 1/4 and 0 <= A <= pi/2.
sin a = 1/4 then cos a = sqrt(15)/4
sin 2α = 2 sin α cos α sin and cos are both positive in Q I (from 0 to pi/2 is Q I )
sin 2a = 2 (1/4) (sqrt(15)/4) <==== take it from here !
+36915 
