Question
Mathematics Question on binomial expansion formula
Let the sixth term in the binomial expansion of (2log2(10−3x)+52(x−2)log23)m, in the increasing powers of 2(x−2)log23, be 21 If the binomial coefficients of the second, third and fourth terms in the expansion are respectively the first, third and fifth terms of an AP, then the sum of the squares of all possible values of x is
Answer
The correct answer is 4.
T6=mC5(10−3x)2m−5⋅(3x−2)=21
mC1,mC2,mC3 are in A.P.
2. mC2=mC1+mC3
Solving for m, we get
m= 2(rejected), 7
Put in equation (1)
21.(10−3x)93x=21
3x=30,32
x=0,2
Sum of the squares of all possible values of x=4