Science:Math Exam Resources/Courses/MATH220/December 2011/Question 01 (a)/Solution 1

De Morgan's laws are, for sets $X,Y\subseteq Z$ the following.

$(X\cup Y{)}^c=X^c\cap Y^c$

and

$(X\cap Y{)}^c=X^c\cup Y^c$

Here the c indicates the complement of the set.