Define \( M(u) = u - \fracu^44 \) for all real \( u \). If \( n \) is a positive integer, define \( b_n \) by \( b_1 = 1 \) and \( b_n = M(b_n-1) \) for \( n \geq 2 \). Compute \( b_3 \). - Appfinity Technologies