If $x = \sum\limits_{n = 0}^\infty {{a^n},\,\,y = \sum\limits_{n = 0}^\infty {{b^n},\,\,z = \sum\limits_{n = 0}^\infty {{c^n},} } } \,\,$ where a, b, c are in A.P and $\,\left| a \right| < 1,\,\left| b \right| < 1,\,\left| c \right| < 1$ then x, y, z are in