# Indeterminate form problems

1. Mar 24, 2008

### blu3jam

Hi I'm new to this forum, i need a help i don't know how can i use l'hospital in these problems;

lim(x->1, ((arccos(x))^lnx))

lim(x->$$\pi$$/2+ (cosx ln(x - $$\pi$$/2 ) )

Can anyone help?

Last edited: Mar 24, 2008
2. Mar 24, 2008

### nicksauce

The second one is greatly simplified if you make a change of variables u = x - pi/2

3. Mar 24, 2008

### blu3jam

Thanks, but still i don't know how can i proceed ? =(

lim(u->0+ (cos(u+$$\pi$$/2) ln(u ) )

4. Mar 24, 2008

### nicksauce

Well cos(u+pi/2) = -sin(u)

Then you can write your function as
-ln(u) / csc(u), and then apply l'hopital's rule. See where that gets you.

5. Mar 24, 2008

### blu3jam

Now ,i figured it out thank you