Maple: How having assumptions for variables to be from real range to solve such equasion?

So I have an equation like this:

I need to get G[xy]. How to tell Maple that we are assuming that G[xx], G[xy] are values from real range (So Im(G[xx]) 开发者_如何学Python== 0 and Re(G[xy]) == G[xy]) and find G[xy] from Im(solution[1][1])?

Use assume or assuming. In your case:

solve(Im(G[x,x]) = -38/(845*Pi) + Re(G[x,y]), G[x,y]) assuming G[x,y] :: real, G[x,x] :: real;

would work.

I prefer to not use assuming for this kind of thing, as it gives the potentially misleading impression that solve is robust with respect to handling and working with assumptions.

By using evalc to preprocess the system. it's a little easier to keep in mind just what solve is handling.

solve( evalc(Im(G[x,x]) = -38/(845*Pi) + Re(G[x,y])), G[x,y] );

                           38  
                         ------
                         845 Pi

evalc(Im(G[x,x]) = -38/(845*Pi) + Re(G[x,y]));

                         38            
                 0 = - ------ + G[x, y]
                       845 Pi          

It's a personal preference, and you may well come up with reasons to prefer going the other route, as a rule. Or perhaps sometimes both methods will find their niche.