We explicitly construct a finite set of separating invariants for the basic G(a)-actions. These are the finite dimensional indecomposable rational linear representations of the additive group G(a) of a field of characteristic zero, and their invariants are the kernel of the Weitzenbock derivation D-n = x(0) partial derivative/partial derivative x1 + ... + x(n-1) partial derivative/partial derivative x(n).