Question

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矩陣A滿足方程式X²-2X-31=0,則求4的乘法反元素為何?
-(a+d) = -2
a b
d]
c d
del (A) =
ad-bc
ad-bc = -1.
7
ad-bc
[de]
门

Answer 1

qn

X²-2XI-3I²=0
(X-3I)(X+I)=0
X= 3I 或 -I
X⁻¹= ⅓I 或 -I