​​The sum of coefficients of x^{2/3} and x^{2/5} in the binomial expansion of (x^2/3 + x^{-2/5} / 2)^9 is

Question

The sum of coefficients of \(x^\frac 23\) and \(x^\frac 25\) in the binomial expansion of \(\left(x^{\frac 23} + \frac{x^{\frac{-2}5}}2 \right)^9\) is

(1) \(\frac{^9C_4}{2^5}\)

(2) \(\frac{^9C_6}{2^4}\)

(3) \(0\)

(4) \(\frac {63}8\)

Answer 1

Correct option is (1) \(\frac{^9C_4}{2^5}\)