当 n = 5,矩阵 C 有___个余子式。每个 4x4 余子式有___项,每项有___次乘 法。段落 2.4 中计算 A 逆 的高斯-乔丹法需要 5^3 = 125,比较两者的差异。
For n = 5, C contains 25 cofactors and each 4 by 4 cofactor has 24 terms. Each term needs 3 multiplications: total 1800 multiplications vs.125 for Gauss-Jordan.