Limit at -infinity problem  TOPIC_SOLVED

Limits, differentiation, related rates, integration, trig integrals, etc.

Limit at -infinity problem

Postby jsel on Fri Oct 15, 2010 7:42 pm



The best thing I could think to do here is multiple the numerator and denominator by the conjugate radical sqrt(x^2 + x + 1) - x. But that will lead to a 0 in the denominator once x is factored out. Ialso tried breaking up the quadratic under the radical into factored form, but it has no solutions. Can someone give me a hint?
jsel
 
Posts: 7
Joined: Mon Oct 11, 2010 11:07 pm

Sponsor

Sponsor
 

Re: Limit at -infinity problem  TOPIC_SOLVED

Postby stapel_eliz on Fri Oct 15, 2010 9:00 pm

jsel wrote:

The best thing I could think to do here is multiple the numerator and denominator by the conjugate radical sqrt(x^2 + x + 1) - x. But that will lead to a 0 in the denominator....

Not actually.

Since and since will be (very, very) negative, then the square root will "simplify" to .

Where would this lead? :wink:
User avatar
stapel_eliz
 
Posts: 1704
Joined: Mon Dec 08, 2008 4:22 pm

Re: Limit at -infinity problem

Postby jsel on Sun Oct 17, 2010 4:47 pm

Got it, thanks. I forgot about that property when taking the square root of x^2
jsel
 
Posts: 7
Joined: Mon Oct 11, 2010 11:07 pm

Postby stapel_eliz on Sun Oct 17, 2010 9:34 pm

jsel wrote:I forgot about that property when taking the square root of x^2

Everybody does. Expect a trick question using this property on the test. :wink:
User avatar
stapel_eliz
 
Posts: 1704
Joined: Mon Dec 08, 2008 4:22 pm


Return to Calculus