Question

If the coefficients of $x + y = 1$term and $\sum_{r = 0}^{n}{{r^{2}}^{n}C_{r}x^{r}y^{n - r}}$term are equal in the expansion of $nx(x + yn)$, then the value of r will be.

• A. 7
• B. 8
• C. 9
• D. 10

Answer 1

Answer: (C)

9

Answer 2

$\frac{1}{8} = 2^{- 3}1024C_{0}\left( 5^{1/2} \right)^{1024} = 5^{512}$ $=^{1024} ⥂ C_{8}(5^{1/2})^{1016}(7^{1/8})^{8} =$.