wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The value of a20a21+a22....a22n is

A
an
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
2an
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
3an
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
n+12(a0+a1+a2...a2n)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A an
(1+x)2n=1+2nC1x+2nC2x2+....+2nC2nx2n
or,
(1+x)2n=a0+a1x+a2x2+...+a2nx2n ...(i)
Similarly,
(1x)2n=a0a1x+a2x2+...+a2nx2n ....(ii)
As, a0=a2n, a1=a2n1,...and so on. So, (i) and (ii) can be written as:
(1x)2n=a2na2n1x+a2n2x2+...+a0x2n
(1+x)2n=a0+a1x+a2x2+...+a2nx2n

So, required answer is coefficient of x2n in (1+x)2n.(1x)2n= coefficient of x2n in (1x2)2n
Tr+1=2nCr(x2)r
=2nCr(1)r(x)2r
So, we need, r=n. Hence, the answer is (1)n.an
For neven, the answer is option A, i.e; an

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Sum of Coefficients of All Terms
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon