How to compute relative homology group $H_n(SO(n),SO(n)-E_n)$
I try to use the long exact sequence as follows $$
...H_n(SO(n)-E_n)\rightarrow H_n(SO(n))\rightarrow H_n(SO(n),SO(n)-E_n) \rightarrow H_{n-1}(SO(n)-E_n)...$$
I find difficulty both in compute $H_n(SO(n))$ and $H_n(SO(n)-E_n)$