In[1]:= Solve[{m^3 + n^3 + 99 m n == 33^3, m >= 0, n >= 0}, {m,
n}, Integers]
Out[1]= {{m->0,n->33},{m->1,n->32},{m->2,n->31},{m->3,n->30},{m->4,n->29},{m->5,n->28},{m->6,n->27},{m->7,n->26},{m->8,n->25},{m->9,n->24},{m->10,n->23},{m->11,n->22},{m->12,n->21},{m->13,n->20},{m->14,n->19},{m->15,n->18},{m->16,n->17},{m->17,n->16},{m->18,n->15},{m->19,n->14},{m->20,n->13},{m->21,n->12},{m->22,n->11},{m->23,n->10},{m->24,n->9},{m->25,n->8},{m->26,n->7},{m->27,n->6},{m->28,n->5},{m->29,n->4},{m->30,n->3},{m->31,n->2},{m->32,n->1},{m->33,n->0}}
数一数,共有 34 组,考虑到 m, n 在方程中的对称性, 只有 17 组解。 |