D and E are sets of real numbers defined as follows.

Question

D= {v│v > 4}

E= {v│v ≤ 7}

Write D U E and D ∩ E using interval notation. If the set is empty, write Ø

Answer 1

D ∪ E = {v l v > 4 or v ≤ 7} = (-∞, ∞)

D ∩ E = {v l v > 4 and v ≤ 7} = (4, 7]