px1+x2+x3=1, x1+px2+x3=p, x1+x2+px3=p².当p取何值时,方程组有唯一解,无解,有无穷解并求通解.
问题描述:
px1+x2+x3=1, x1+px2+x3=p, x1+x2+px3=p².当p取何值时,方程组有唯一解,无解,有无穷解并求通解.
答
解: 系数行列式|A| = (λ+2)(λ-1)^2.所以当 λ≠1 且 λ≠-2 时方程组有唯一解.当λ=1时, 增广矩阵 =1 1 1 11 1 1 11 1 1 1r2-r1,r3-r11 1 1 10 0 0 00 0 0 0此时方程组有无穷多解: (1,0,0)'+c1(...