D u(En F)= {h, m, u, b, l, e, a, r}
The given sets are:
U= {a, b, c, d ,...,x,y,z}
D = {h, u, m; b, l, e}
E = {h; a; m, p; e; r}
F = {t, r, a, s, h}
To find Du(En F), we need to apply the following set theory formula:
Du (En F) = (Du En) U (Du F')
Here, En and F' are the complement of F with respect to U and D, respectively.
So, let's first find En:En = U ∩ E = {a, h, m, e, r}
Now, let's find F':F' = D - F = {u, m, b, l, e}Du = {h, u, m, b, l, e}
Using the formula, we get:
D u(En F) = (Du En) U (Du F')
= ({h, m, u, b, l, e} ∩ {a, h, m, e, r}) U ({h, u, m, b, l, e} ∩ {u, m, b, l, e})
= {h, m, u, b, l, e, a, r}
Answer: {h, m, u, b, l, e, a, r}