Question

If the middle term in the expansion of (x + b/x)⁶ is 160, find b.

Answer 1

Here, a = x, b = b/x, n = 6.

Now, n is even.

\(\therefore\) \(\frac{n+2}2=\frac{6+2}2=4\)

\(\therefore\) Middle term is t₄, for which r = 3

\(\therefore\) t₄ = 160

We have 

\(\therefore\) 160 = b³

\(\therefore\) b = 2