先从第一列开始,每一列依次减去后一列,得到{{1,0,0,...,1},{-3,1,0,...,1},{0,-3,1,...,1},...,{0,0,0,...,2}},懂?然后,再从新矩阵的第一行开始,每行依次乘以3,再加到后一行,得到{{1,0,0,...,1},{0,1,0,...,4},{0,0,1,...,13},...,{0,0,0,...,(3^n+1)/2}},懂?然后,原式=1*1*...*[(3^n+1)/2]=(3^n+1)/2。嗯,最后就搞定了。呵呵,线代不好学啊,慢慢来。...
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