An arithmetic sequence has first term aaa and common difference ddd.
The sum of the first 9 terms of the sequence is equal to the square of the sum of the first 3 terms.
Show that a+4d=a2+2ad+d2a + 4d = a^2 + 2ad + d^2a+4d=a2+2ad+d2
Given that the fifth term of the sequence is 9, find the smallest possible value of aaa.
