Find the degree of the polynomial `1/(sqrt(4x+1)){((1+sqrt(4x+1))/2)^7-((1+sqrt(4x+1))/2)^7}`

Answer

`n=11` or `12`

Explanation

We have, `(1)/(sqrt(4x+1)) ={((1+sqrt(4x+1))/(2))^(n)-((1-sqrt(4x-1))/(2))^(n)}`
`= (1)/(2^(n)sqrt(4x+1)){2[.^(n)C_(1)sqrt(4x+1)+.^(n)C_(3)(sqrt(4x+1))^(3)+"....."]}`
`= (1)/(2^(n-1))[.^(n)C_(1)+.^(n)C_(3)(sqrt(4x+1))^(2)+.^(n)C_(5)(sqrt(4x+1))^(4)+"....."]`
Since R.H.S. of the given expression contains `x^(5)`. so this expression should go up to `(sqrt(4x+1))^(10)` and hence `n = 11` or `12`.