20 20 If the coefficient of 4th term in the expansion of x + α2xn is - Maths - Binomial Theorem

Question

20?
20 If the coefficient of 4th term in the expansion of x
  +   α 2 x n   i s   20   t h e n
  t h e   r e s p e c t i v e   v a l u e s   o
f   α   a n d   n   a r e  
a) 2,7 b) 5,8 c) 3,6 d) 2,6 20 ?

Aarushi Mishra · Accepted Answer

General term of the given expansionTr+1=Crn xn-r α2xrT4=C3n xn-3 α2x3Given: T4=C3n xn-3 α2x3=20C3n xn-6 α38=20 x0Comparing both sidesPower of x on both sides must be same n-6=0n=6Put n=6C36 x6-6 α38=20 x06×5×43×2×1 α38=20α38=1α3=8α=2
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20? 20. If the coefficient of 4th term in the expansion of x + α 2 x n i s 20 . t h e n t h e r e s p e c t i v e v a l u e s o f α a n d n a r e a) 2,7 b) 5,8 c) 3,6 d) 2,6 20 ?

20?
20. If the coefficient of 4^th term in the expansion of ${(x + \frac{α}{2 x})}^{n} i s 20 . t h e n t h e r e s p e c t i v e v a l u e s o f α a n d n a r e$
a) 2,7 b) 5,8 c) 3,6 d) 2,6 20 ?