# Indeterminate form problems

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:

## Answers and Replies

Related Calculus and Beyond Homework Help News on Phys.org
nicksauce
Science Advisor
Homework Helper
The second one is greatly simplified if you make a change of variables u = x - pi/2

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

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

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

nicksauce
Science Advisor
Homework Helper
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.

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.
Now ,i figured it out thank you