
Inverting a matrix
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

Just checking I'm following what you're after: if you call your original matrix A, and your inverse is A^1, you want A^1A = I?
If so, your inverse is
a/(a^2  1) 1/(a^2  1)
1/(a^2  1) a/(a^2  1)
If your original matrix was its own inverse, then AA=I, but in your case AA =
a^2 + 1 0
0 1 + a^2
Which is (a^2 + 1)I, but not I itself.

yeah thats right...thanks heaps mate
i think ive worked out what i need to know now, thanks heaps