A) -20
B) 20
C) 30
D) -30
Correct Answer: A
Solution :
[a] : In the expansion of\[{{\left( x-\frac{1}{x} \right)}^{6}}\], the general term is \[^{6}{{C}_{r}}{{x}^{6-r}}{{\left( -\frac{1}{x} \right)}^{r}}={}^{6}{{C}_{r}}{{(-1)}^{r}}{{x}^{6-2r}}\]. For term independent of \[x,6-2r=0\Rightarrow r=3\] So, the required constant term \[={{(-1)}^{3}}{{.}^{6}}{{C}_{3}}=-20\]You need to login to perform this action.
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