Question
The coefficient of the middle term in the binomial expansion in powers of x of (1 +αx)4 and of (1−αx )6 is the same if α equals
-
-5/3
-
3/5
-
-3/10
-
10/3
Solution
C.
-3/10
The coefficient of x in the middle term of expansion of (1+ αx)4= 4C2.α2
The coefficient of x in middle term of the expansion of 3(1− αx) = 6C3 (−α)3
According to question