Or put in another way, how to make a variable behave as it belongs to a specific domain, even outside the use of simplify or other commands alike?
Re[u] because the kernel cannot tell upfront that
u is real.
Even after setting
$Assumptions = u ∈ Reals, a call to
Re[u] keeps returning
Re[u]. A call to
Re[u] // Simplify works.
But it would be simpler to make a variable behave always like assumed without the need to a call to
Simplify. On the other hand a call to
Is there a way to make variables behave like π does in the example above?