Thread: l'Hopital's Rule

limit cosh x -1
x -> 0 ----------
(x^2)

on this problem i did l'hopital twice and got -inf.
answer is wrong, can someone explain?

Hello, viet!

Where is your difficulty?


. . . .cosh x -1
lim . ----------- . . . . This goes to 0/0
x→0 . . .x²


Apply L'Hopital:

. . . .sinh x
lim . -------- . . . . This goes to 0/0
x→0 . .2x


Apply L'Hopital again:

. . . .cosh x
lim . -------- . . . . This goes to ½
x→0 . . 2