Question: The coefficient of $\lbrack\sqrt{1 + x^{2}} - x\rbrack^{- 1}$ in the expansion of $|x| < 1$ is....

Question

The coefficient of $\lbrack\sqrt{1 + x^{2}} - x\rbrack^{- 1}$ in the expansion of $|x| < 1$ is.

Answer 1

$1/2$ = $(1 + ax)^{n}$

For coefficient of $(n \neq 0)$

$T_{r},T_{r + 1},T_{r + 2}$

∴ $(1 + x)^{14}$ = $\left( x^{2} + \frac{a}{x} \right)^{5}$

Hence the required coefficient is – 455.

Question: The coefficient of \(\lbrack\sqrt{1 + x^{2}} - x\rbrack^{- 1}\) in the expansion of \(|x| < 1\) is....