If \( \mathop a\limits^ \to \), \(\mathop b\limits^ \to \) and \(\mathop c\limits^ \to \) are three vectors in such a way that \(\mathop a\limits^ \to +\mathop b\limits^ \to + \mathop c\limits^ \to = \mathop 0\limits^ \to \) and \(|\mathop a\limits^ \to | = 1, |\mathop b\limits^ \to | = 4, |\mathop c\limits^ \to | = 2\), then the value of \(2(\mathop a\limits^ \to.\mathop b\limits^ \to + \mathop b\limits^ \to.\mathop c\limits^ \to+\mathop c\limits^ \to.\mathop a\limits^ \to)\) is equal to