Question

The expression $\frac{1}{\sqrt{4x + 1}}\left\{ \left( \frac{1 + \sqrt{4x + 1}}{2} \right)^{7}–\left( \frac{1–\sqrt{4x + 1}}{2} \right)^{7} \right\}$is a polynomial in x of degree

• A. 7
• B. 5
• C. 4
• D. 3

Answer 1

Answer: (D)

3

Answer 2

$$$\left. \ +^{7}C_{5}\left( \sqrt{4x + 1} \right)^{5} +^{7}C_{7}\left( \sqrt{4x + 1} \right)^{7} \right\rbrack$ It is polynomial of degree 3