Prove that there is no term involving $x^{6}$ in the expansion of $\left(2 x^{2}-\frac{3}{x}\right)^{11}$.
To prove: that there is no term involving $x^{6}$ in the expansion of $\left(2 x^{2}-\frac{3}{x}\right)^{11}$
Formula Used:
General term, $T_{r+1}$ of binomial expansion $(x+y)^{n}$
is given by,
$T_{r+1}={ }^{n} C_{r} x^{n-r} y^{r}$ where
${ }^{n} C_{r}=\frac{n !}{r !(n-r) !}$
Now, finding the general term of the expression, $\left(2 x^{2}-\frac{3}{x}\right)^{11}$, we get
$\mathrm{T}_{\mathrm{r}+1}={ }^{11} \mathrm{C}_{\mathrm{r}} \times\left(2 x^{2}\right)^{11-r} \times\left(\frac{-3}{\mathrm{x}}\right)^{\mathrm{r}}$
For finding the term which has ${ }^{x}{ }^{6}$ in it, is given by
$22-2 r-r=6$
$3 r=16$
$r=\frac{16}{3}$
Since, $r=\frac{16}{3}$is not possible as $r$ needs to be a whole number
Thus, there is no term involving $x^{6}$ in the expansion of $\left(2 x^{2}-\frac{3}{x}\right)^{11}$.