Using Refine function and take real part of a symbolic expression

2018-03-13 17:02:26

I am trying to take the real part of the a complex expression using Refine function.

However, the result doesn't come out as expected. The final result still contains Im function.

Does anyone have some idea what is going on here?

expr = x + (I*(y + z))/(m + I*n);

evar = Variables[expr];

Refine[Re[expr], Element[evar, Reals]]


x - (y + z)*Im[1/(m + I*n)]