[JEE Advanced 1999] In $(1+x)^m(1-x)^n$ the coefficients of $x$ and $x^2$ are $3$ and $-6$. Then $m$ is
In $(1+x)^m(1-x)^n$ the coefficients of $x$ and $x^2$ are $3$ and $-6$. Then $m$ is
(a) $6$
(b) $9$
(c) $12$
(d) $24$
1 Answer
VAVidaara Admin
✓ Vidaara Team
✓ Accepted
· 1mo ago
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Correct answer: (c) $12$
$m-n=3$ and $\frac{(m-n)^2-(m+n)}2=-6\Rightarrow m+n=21$, so $m=12$.
JEE Advanced 1999 · Binomial Theorem — verified solution by the Vidaara Team.
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