例7-25  符號矩陣的逆和行列式運算。
解：在命令窗口中輸入如下命令，并按Enter鍵確認。
>> h=sym(hilb(4))
h = 
[   1, 1/2, 1/3, 1/4]
[ 1/2, 1/3, 1/4, 1/5]
[ 1/3, 1/4, 1/5, 1/6]
[ 1/4, 1/5, 1/6, 1/7]
>> inv(h)
ans =
[    16,  -120,   240,  -140]
[  -120,  1200, -2700,  1680]
[   240, -2700,  6480, -4200]
[  -140,  1680, -4200,  2800]
>> det(h)
ans =
 1/6048000
>> b=sym('[1,x;x;x^2]')
 
b =
[1,x],[x],[x^2]
>> inv(b)
??? Error using ==> sym/inv
Error, invalid terms in product
>>