4i 8 D/\ hutton on Cubic Equations 
confequently this is equal to the former feries, or 
2 x : i 
*-■ * 8 Sec. = i + — 2 
8cc. 
3.6 3.6.9.12 3 3.6 3.6.9 
= 2. Hence, By fubtradti-ng 1 — — ™ See. 
from both fides, we have 
I - 2 Sec. Li- 1 - - 11 .- 8ec. 
3.6 3.6.9.12 ' 3 '3.6.9 3.6.9.12.15 
which multiplied by is/b will alfo give the root of the 
fame equation. And hence, adding - + ■■ 2 ' 5 ' 8 . 8cc. 
1 0 3 . 6 3.6.9.12 
to both fides of the laft equation, we find that 
I IS = — + — -~~r 4- 7~ + , " ■ + — — ~ See. 
I 2 2 .X 2.5.8 2 * 5 . 8 . 11 * 
{- 4. — {- — 2 -| =L_ — 
3 3.6 3.6.9 3.6.9.12 3.6. 9.12.15 
Or, farther, multiplying by 3, and fubtradting 1, we have 
6 6.9 6.9.12 6.9.12.15 
74. Alfo from 2 x : 1 - — T ^- 8 - Sec. = 4/2 in 
* r 3.63.6.9.12 
the laft article, we find \y 2 = 
1 _ 2 See. = -i + -^- 5 - + 
3.6 3.6.9.12 3 3.6.9 3.6.9.12.15 
Sec. 
75. In this cafe alfo, namely, c - h, the equa- 
tion d — 'd'b - c — yb x : 1 — -- — 8 ec, becomes 
36 3.6^- 
o = yb x : 1 — — — — -A- Sec. 
3 3- 6 3-6.9 
And hence, dividing by yb, and adding, we have 
1 := — 
3 
» + &c. 
3.6 3.6.9 3.6.9. 12 
the fame as in the laft article but one. 
76. And 
