Question

The rth term of expansion of $\left[\begin{array}{ccc} x + 1/ x \\\\\end{array}\right]^ {2r}$

Answer 1

Yo sup??

$T_r=^2^rC_r_-_1x^r^-^1(1/x)^r^-^1\\=^2^rC_r_-_1\\=(2r)!/((r-1)!)^2$

$where \\^nC_r=n!/(n-r)!*r!$

Hope this helps.