486 ON THE SUMMATION OF SERIES, 
Cor. If we take n=1, 2, 3, 4, &c. successiv ely 
we shall have 
2m+a 
z -(m+ax)=—= yee - 
wv 
3 
2 2 2 2 
oS +(ma += )w = 5 (m + am 
v 2 
sire (m+ax) = 
0 
a” 
+=) eer 
4 3 3,4 
Day te (m+az) = +(ma?+$ ‘le Bee cps 
0 
3m*a 
++ \e +(m* +4) a. 
Ex. 4.—Required the sum of a terms of the 
series whose general term is 
a+bet+cr+da+er+ &e., &e. 
Here we shall have f (#)=a+ba+e2?+ &c.; 
\ PG) dear yy" + ge) Be; F (eyo 
2c4+3d2’ + &c., &c. ; f (x)=2.3d+2.3.4eu-+ 
3.4.5fa°+ &e, &e. f(x) = [5] f+ [6] ext 
[3, 7] ha + &c., &e. Where [3, 7] =3.4.5.6.7, 
and generally [2, y] = x(x+1) («+2) to y: 
