Problem 418 - Warren Truss by Method of Sections

Problem 418
The Warren truss loaded as shown in Fig. P-418 is supported by a roller at C and a hinge at G. By the method of sections, compute the force in the members BC, DF, and CE.



Solution 418



can you please elobarate , how to get 1 and 2 , i know the process but i dont know how you get 1 and 2