Browse Questions

# Find the middle term in the expansion of $(\large\frac{x}{a}-\frac{a}{x})^{10}$

$\begin{array}{1 1}(A)\;251\\(B)\;252\\(C)\;-252\\(D)\;254\end{array}$

Toolbox:
• If $n+1$ is odd,the middle term is $\large\frac{(n+1)+1}{2}$$+h=\large\frac{n+2}{2}$$+h$
• $T_{r+1}=(-1)^rnC_ra^{n-r}b^r$
Number of terms in the expansion is 10+1=11