Remark Proceeding as in Example 34 one may prove that the two positive numbers,
whose sum is k and the sum of whose squares is minimum, are 
2and
2
k
k Example 23 Find the shortest distance of the point (0, c) from the parabola y = x2,
where 1
2  ≤ c ≤ 5 Solution Let (h, k) be any point on the parabola y = x2 Let D be the required distance
between (h, k) and (0, c)