Question

if the square of the matrix
[a b
a -a ] is the unit matrix then b is equal to​

Answer 1

Answer:

step 1:[a b

a -a][a b

a -a]=[1 1

1 1]

step 2:[a^2+ab ab-ba

a^2-a^2 ab+a^2]=[1 1

1 1]

step 3:[a^2+ab 0

0 a^+ab]=[1 1

1 1]

step 4:a^2+ab=1

step 5:a(a+b)=1

step 6:a=1,a+b=1

1+b=1

b=0