Originally Posted by

**kpc** I am sorry if this question is asked in the wrong section. It looks to me as if matrix theory is not educated pre-university in the US?

Given A, a complex symmetric large matrix (N>>1000), with elements near the diagonal |r-k| < approx. 10. values decaying as we go further from the diagonal.

Is it possible to symbolically write the following

(I+A)^-1

in a manner without the inverse?

Could it be approximated using a series development?

Edit: just forget about the b in the title, it is just a constant.