Answer:
[tex]\begin{aligned}\lbrace & \; 3,\, 5,\, 6,\, 7,\, 9,\, 10, \\ &\; 11,\, 12,\, 13,\, 14,\, 15,\, 17, \\ &\; 18,\, 19,\, 20\rbrace\end{aligned}[/tex].
Step-by-step explanation:
The integer powers of [tex]2[/tex] between [tex]1[/tex] and [tex]20[/tex] are:
Thus, [tex]A = \lbrace 1,\, 2,\, 4,\, 8,\, 16 \rbrace[/tex].
The complement of set [tex]A[/tex] (denoted as [tex]A^{C}[/tex]) includes all elements of the universal set [tex]U[/tex] that are not in set [tex]A\![/tex].
For example, the element [tex]1[/tex] is in [tex]U[/tex] and is also in [tex]A[/tex]. Thus, [tex]1[/tex] isn't in [tex]A^{C}[/tex].
The element [tex]3[/tex] is in [tex]U[/tex] and isn't in [tex]A[/tex]. Thus, [tex]3[/tex] is in [tex]A^{C}[/tex].
Repeat this decision process for each element of [tex]U[/tex] to enumerate [tex]A^{C}[/tex]:
[tex]\lbrace 3,\, 5,\, 6,\, 7,\, 9,\, 10, \, 11,\, 12,\, 13,\, 14,\, 15,\, 17, \, 18,\, 19,\, 20\rbrace[/tex].