7.Binomial Theorem
medium

The coefficient of $x^5$ in the expansion of $\left(2 x^3-\frac{1}{3 x^2}\right)^5$ is

A

$8$

B

$9$

C

$\frac{80}{9}$

D

$\frac{26}{3}$

(JEE MAIN-2023)

Solution

$\left(2 x^3-\frac{1}{3 x^2}\right)^5$

$T_{r+1}={ }^5 C_r\left(2 x^3\right)^{5-r}\left(\frac{-1}{3 x^2}\right)^r={ }^5 C_r \frac{(2)^{5-r}}{(-3)^r}(x)^{15-5 r}$

$\therefore 15-5 r =5$

$\therefore r =2$

$T_3=10\left(\frac{8}{9}\right) x^5$

So, coefficient is $\frac{80}{9}$

Standard 11
Mathematics

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