Q. Coefficient of the term independent of $x$ in the expansion $\left( x + \frac{1}{x^{2}} \right)^{6}\ is\ equal\ to$

A) 10
B) 15
C) 16
D) None of the above
Explanation

(b)
$General\ term,\ T_{r + 1} = \ ^{6}C_{r}x^{6 - r}\left( \frac{1}{x^{2}} \right)^{r}$
$\Longrightarrow T_{r + 1} = \ ^{6}C_{r}x^{6 - 3r}$
For term independent of $x,$ put
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 6 - 3r = 0$
$\Longrightarrow r = 2$
$\therefore$ Coefficient of independent term $= \ ^{6}C_{2} = 15$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.