174 DEFLECTION OF BEAMS 



-. 1 I 2 3 



(26) 



R 3 may be found in a similar manner by drawing an equilibrium 

 polygon for a load, 1-3-4, through point n. 



When R 2 and R 3 have been obtained, the reactions R^ and R can 

 most easily be obtained by algebraic moments. 



Proof. With the load, 124, an d full line deflection curve we 

 have, as in the case of three supports, 



P tg (27) 



And with the load, 1-3-4, and dotted line deflection curve we 

 have, in like manner, 



R s k= -R 2 h + P ie + P 2 f + P 3 (c + g) (28) 



Subtracting (28) from (27) we have 



, 2 s 



R 2 =- (29) 



a 



which is the equation of which proof was required. 



