Question -
Answer -
It is known that (r +1)th term, (Tr+1), in the binomialexpansion of (a + b)n is givenby 
.
Assuming that x2 occursin the (r + 1)th term of the expansion (1 +x)m,we obtain
Comparing the indices of x in x2 andin Tr + 1, we obtain
r = 2
Therefore, the coefficientof x2 is 
.
It is given that the coefficientof x2 in the expansion (1 + x)m is6.
Thus, the positive value of m,for which the coefficient of x2 in the expansion
(1 + x)m is6, is 4.