58 
MEMORIAS CIENTIFICAS I LITERARIAS 
V = 
/■ 
d t b — 2 x 
= arc cos 
l/l — t 2 
26. y 
Sea 
j 
dx 
1 
l/4a + b 2 
(Sturm, 1340) 
d x 
Va+ ox + c x- ]/ c 
’ b \ s 4ac— b‘ 
x + ■ ~ — j + 
2c) 4 c 2 
x + o c Z 
d x= d z 
1 
v = — 7 = L [2cx + b + 2 V c Va + bx + 6x : 
V c 
27. v 
-/■ 
3 x — 2 
dx 
]/4 x 2 + 16 x + 20 ^ J 1/4 [(x — 2) 2 + 1 ] 
(Todhunter, 12; 
3 x— 2 
d x 
Sea 
x = 2 + u 
v = 
u d u 
2.1 
y u 2 +i 
dx = d u 
d u 
2 L [ (x — 2)+ Vx s — 4x + 5) + y V x 2 — 4x + 5 
28. y = / e a x d x . Sea a x = z . • . dx= — d z 
a 
