Using the generalized binomial series, find the coefficient of x4x^4x4 in (1+x)−1/2(1+x)^{-1/2}(1+x)−1/2.
−5128-\frac{5}{128}−1285
35128\frac{35}{128}12835
−35128-\frac{35}{128}−12835
5128\frac{5}{128}1285