3. Mathematically show that if d(n) is O(f (n)) and e(n) is O(g(n)), d(n) +e(n) is O(f(n) +g(n)

3. Mathematically show that if d(n) is and e(n) is d(n) + e(n) is + g(n)) 3. Mathematically show that if d(n) is and e(n) is d(n) + e(n) is + g(n))