Since rth term from the end in the expansion of (a + b)n is (n – r + 2) th term from the beginning. Therefore 4th term from the end is 9 – 4 + 2, i. e., 7 th term from the beginning, which was given by
OR
4th term from the end of \((\frac{x^2}{2}-\frac{2}{x^3})^9\)
= 4th term from the beginning \((\frac{-2}{x^3}+\frac{x^2}{2})^9\)