Question

How do you find `E^-1` given `E=((1, -1), (1, 1))` ?

Answer 1

`1/2 ((1,1),(-1,1))`

Explanation:

`((a,b),(c,d))^-1 =1/(ad - bc) ((d,-b),(-c,a))`

here that's

`1/(1 * 1 - (-1) * 1) ((1,1),(-1,1))`

`1/2 ((1,1),(-1,1))`