a 1

1 -a

i find the inverse, which is

a/(a^2 + 1) 1/(a^2 + 1)

1/(a^2 + 1) -a/(a^2 + 1)

which is correct, no?

so can i multiply that matrix by $\displaystyle (a^2 + 1)$ and get this matrix

a 1

1 -a

which is the same as the initial matrix? so is it true that that matrix is its own inverse?

Sorry guys but i cant seem to work out how to do matrices in here properly