Middle term in expansion of {left( {3x - frac{{{x^3}}}{6}} right)^9} are :-

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7.Binomial Theorem

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The middle term in the expansion of ${\left( {3x - \frac{{{x^3}}}{6}} \right)^9}$ are :-

A

$ - \frac{{21}}{{16}}{x^{19}},\frac{{189}}{9}{x^{17}}$

B

$\frac{{21}}{{16}}{x^{19}},-\frac{{189}}{8}{x^{17}}$

C

$\frac{{201}}{{18}}{x^{17}},\frac{{21}}{{16}}{x^{18}}$

D

none of these

Solution

$n = 9$
No. of terms $= 10$
Middle term $= 5^{th}$ & $6^{th}$

Standard 11

Mathematics

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