Question

B= { x | x = 2 ^n,0<n ≤ 4 ;

Answer 1

0<n ≤ 4⇒n∈{1,2,3,4}
x = 2 ^n⇒x=2¹=2

x=2²=4
x=2³=8
x=2⁴=16

B={2,4,8,16}