1. The problem statement, all variables and given/known data Is this statement correct? If the nth term of a sequence is a quadratic expression in n, then the sequence is an A.P. 2. Relevant equations 3. The attempt at a solution Take arbitrary t(n)=n^2-2n-2 I substituted 1,2,3 in the above expression and noted the c.d. It is not constant. But the book says that this statement is correct. Any ideas?