JEE Mains · Maths · STD 11 - 7. binomial theoram
If the coefficients of \(x^{7}\) in \(\left(x^{2}+\frac{1}{b x}\right)^{11}\) and \(x^{-7}\) in \(\left(x-\frac{1}{b x^{2}}\right)^{11}, b \neq 0\), are equal, then the value of \(b\) is equal to:
- A \(-1\)
- B \(2\)
- C \(-2\)
- D \(1\)
Answer & Solution
Correct Answer
(D) \(1\)
Step-by-step Solution
Detailed explanation
Coefficient of \(x^{7} \operatorname{in}\left(x^{2}+\frac{1}{b x}\right)^{11}\) \({ }^{11} \mathrm{C}_{\mathrm{r}}\left(\mathrm{x}^{2}\right)^{11-\mathrm{r}} \cdot\left(\frac{1}{\mathrm{bx}}\right)^{\mathrm{r}}\)…
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