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Ex 1C
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Solutions
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(i)
\begin{align*} A \cap B & = \{ 2, 4 \} \end{align*}
(ii)
(i)
\begin{align*} C \cap D & = \{ \text{blue, yellow, pink} \} \end{align*}
(ii)
(i)
(ii)
\begin{align*} E \cup F & = \{ 11, 12, 13, 14, 15, 16, 17, 18, 20 \} \end{align*}
(i)
(ii)
\begin{align*} G \cup H & = \{ \text{orange, durian, pear, apple, banana, grape, strawberry} \} \end{align*}
(a)
\begin{align*} \xi & = \{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 \} \\ \\ I & = \{ 4, 8, 12 \} \\ \\ J & = \{ 1, 2, 4, 8 \} \end{align*}
(b)
(c)(i)
\begin{align*} (I \cup J)' & = \{ 3, 5, 6, 7, 9, 10, 11, 13, 14, 15 \} \end{align*}
(c)(ii)
\begin{align*} I \cap J' & = \{ 12 \} \end{align*}
(i)
(ii)
(iii)
(i)
\begin{align*} M & = \{ 1^2, 2^2, 3^2, 4^2, 5^2, 6^2, 7^2, 8^2 \} \\ & = \{ 1, 4, 9, 16, 25, 36, 49, 64 \} \\ \\ P & = \{ 1^3, 2^3, 3^3, 4^3 \} \\ & = \{ 1, 8, 27, 64 \} \end{align*}
(ii)
(iii)
\begin{align*} M \cap P & = \{ 1, 64 \} \end{align*}
(i)
\begin{align*} N & = \{ 8, 16, 24, 32 \} \\ \\ Q & = \{ 4, 8, 12, 16, 20, 24, 28, 32 \} \end{align*}
(ii)
\begin{align*} N \cap Q & = \{ 8, 16, 24, 32 \} \end{align*}
(iii)
(iv)
$$ \text{Yes, since } N \text{ is a proper subset of } Q, \text{ every element of } N \text{ is in } Q $$
(i) Composite numbers are numbers with more than 2 factors
\begin{align*} R & = \{ 1, 2, 3, 6, 9, 18 \} \\ \\ S & = \{ 10, 12, 14, 15, 16 \} \end{align*}
(ii)
\begin{align*} R \cap S & = \{ \} \\ \\ \text{Factors } & \text{of 18 are less than or equals to 9 (except 18)} \end{align*}
(iii)
(i)
\begin{align*} T & = \{ 4, 8, 12 \} \\ \\ U & = \{ 1, 2, 3, 4, 6, 8, 12, 24 \} \end{align*}
(ii)
(iii)
\begin{align*} T \cup U & = \{ 1, 2, 3, 4, 6, 8, 12, 24 \} \end{align*}
(iv)
$$ \text{Yes, } T \text{ is a proper subset of } U $$
(i)
\begin{align*} V & = \{ 1, 5, 25 \} \\ \\ W & = \{ 6, 12, 18, 24 \} \end{align*}
(ii)
(iii)
\begin{align*} V \cup W & = \{ 1, 5, 6, 12, 18, 24, 25 \} \end{align*}
(a)
\begin{align*} \xi & = \{4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 \} \\ \\ Y & = \{ 6, 9, 12, 15, 18 \} \\ \\ Z & = \{ 9, 18 \} \end{align*}
(b)
(c)(i)
\begin{align*} (Y \cup Z)' & = \{ 4, 5, 7, 8, 10, 11, 13, 14, 16, 17 \} \end{align*}
(c)(ii)
\begin{align*} Y \cap Z' & = \{ 6, 12, 15 \} \end{align*}
(a)
\begin{align*} \xi & = \{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 \} \\ \\ P & = \{ 2, 3, 5, 7, 11 \} \\ \\ Q & = \{ 0, 1, 4, 6, 8, 9, 10 \} \end{align*}
(b)
(c)(i)
\begin{align*} P \cup Q & = \{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 \} \end{align*}
(c)(ii)
\begin{align*} (P \cup Q)' & = \{ \} \text{ or } (P \cup Q)' = \emptyset \end{align*}
(c)(iii)
\begin{align*} P' \cap Q & = \{ 0, 1, 4, 6, 8, 9, 10 \} \end{align*}
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(i)
$$ A \cap \xi = A $$
(ii)
$$ A \cup \xi = \xi $$
(iii)
$$ A \cap \emptyset = \emptyset $$
(iv)
$$ A \cup \emptyset = A $$
Missing information from the question: Set C is a proper subset of set B
(i)
$$ A \cap B = A $$
(ii)
$$ A \cup B = B $$
(iii)
$$ B \cap C = C $$
(iv)
$$ \text{Not possible to simplify} $$
(v)
$$ (B \cup C) \cap A = B \cap A = A $$
(vi)
$$ (B \cap C) \cap A = C \cap A = \emptyset $$
(vii)
$$ (A \cup C) \cap B = A \cup C $$
(viii)
$$ (A \cap C) \cup B = \emptyset \cup B = B $$