高非线性特性(α>30)的氧化锌压敏电阻 能否重复使用

I have a friend .She is Gaofei .She is 13 years old .She is a middle school student .She studys in Class 1,Grade 7.She is tall with long black hair. She wears glasses.She is well-behave.She likes drawing very much.She often draws picturesn the weekend .She studys hard.She often goes to bed at 8 o'clock in the evening and she gets up at 6 o'clock.She usually do some sports .She likes eating fruits and vegetables.She wants to keep health.Look!Today she wears a red sweater and jeans with a pair of comfortable .She looks very beautiful.
你自己看看合不合适,如果多了或少了,你就自己改改.最好看看有没有语法错误,我没检查过的.

方法:化梯矩阵,秩为非零行数,最高非零子式在首非零元所在列
r1-2r4,r2-2r4,r3-3r4
0 1 2 -1 7
0 -3 -6 3 -5
0 -2 -4 2 0
1 0 3 2 0
r2+3r1,r3+2r1
0 1 2 -1 7
0 0 0 0 16
0 0 0 0 14
1 0 3 2 0
秩为3,第1,2,5列,2,3,4行,构成一个最高非零子式

用勾股定理求出