How do you find the limit #ln(x^2+1)/x# as #x->0#?

2 Answers
Oct 18, 2016

Limit as x->0 of #ln(x^2+1)/x= 0#

Explanation:

Direct application give #0/0#
So we use l'Hôpital rule #(ln(x^2+1)')/(x')=(2x)/(x^2+1)=0/1=0#

Oct 18, 2016

l'Hopital's Rule applies.

#:. lim_(x->0)ln(2x^2 + 1)/x = 0#

Explanation:

If we try to evaluate at the limit we obtain:
#0/0#

This means that l'Hopital's Rule applies.

To apply l'Hopital's Rule, you, compute the derivative of numerator, compute the derivative of the denominator, and then reassemble the two derivatives into a new fraction.

The derivative of the numerator:

#(d[ln(x^2+ 1)])/dx = (2x)/(x^2 + 1)#

The derivative of the denominator:

#(d[x])/dx = 1#

Here is our new expression:

#lim_(x->0) (2x)/(x^2+1)#

l'Hopital's Rule states that the limit of our new expression goes to the limit as the original expression

#:. lim_(x->0)ln(2x^2 + 1)/x = 0#