[JEE Main 2016] if the number of terms in 1 2x 4 x 2 n x 0
If the number of terms in $\left(1-\dfrac2x+\dfrac4{x^2}\right)^n$ ($x\ne0$) is $28$, then the sum of the coefficients of all terms is
(a) $243$
(b) $729$
(c) $64$
(d) $2187$
1 Answer
VAVidaara Admin
✓ Vidaara Team
✓ Accepted
· 2d ago
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Correct answer: (b) $729$
Number of terms $\frac{(n+1)(n+2)}2=28\Rightarrow n=6$; sum of coefficients (put $x=1$) $=(1-2+4)^6=3^6=729$.
JEE Main 2016 · Binomial Theorem — verified solution by the Vidaara Team.
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