Question

The coefficient of $1 + \frac{1}{4} + \frac{1.3}{4.8} + \frac{1.3.5}{4.8.12} + ........... =$ in the expansion of

$\sqrt{2}$ is.

• A. $\frac{1}{\sqrt{3}}$
• B. $(1 + x)^{27 ⥂ / ⥂ 5}$
• C. $x^{r}$
• D. $(1 - 2x)^{- 1/2}$

Answer 1

Answer: (C)

$x^{r}$

Answer 2

$9a^{2}$

$10a^{3}$= $10a^{2}$

∴ Coefficient of x⁵ in the given expression

= Coefficient of x⁵ in

$10a$

= Coefficient of x⁶ in $p^{th}$

= $(p + 1)^{th}$.