In Sagemath, at some point I end up with the following expression (with b > 0):

Which would be easy to simplify using the
arctan(x) + arctan(1/x) = pi / 2 equality.
My problem is: how do I simplify using that inequality? I tried simplify_trig() and simplify_full() but none of them worked.
Should I use something like assume( arctan(1/sqrt(b-1)) + arctan(sqrt(b-1))) == pi / 2) ? That looks like a ugly hack