$\"\"$

The binomial expression is $\"\"$ .

Find the fourth term coefficient in the $\"\"$ .

$\"\"$ term in the binomial expansion $\"\"$ is $\"\"$ , where $\"\"$ .

Here $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ in the formula.

$\"\"$

$\"\"$ .

Threfore, the coefficient of the sixth term in the expansion of $\"\"$ is $\"\"$ . $\"\"$

The coefficient of the fourth term in the expansion of $\"\"$ is $\"\"$ .