Questions - Answers
1. If the 2nd, 3rd and 4th terms in the expansion of (a+x)n are respectively 240, 720 and 1080. Find the values of a, x, n.
3. If the coefficients of rth, (r+1)th and (r+2)th terms in the expansion of (1+x)n are in A.P then show that n2 - (4r+1)n +4r2 - 2 = 0.
