Posted by Stuck on Saturday, February 6, 2010 at 3:04pm.
How do I solve lim((3x^3  5x +2)/(4x^2 + 3)) as x approaches infinity?
I divided everything by the largest power of x, but I ended up getting a denominator of 0. Do I have to factor this?
(answer is infinity)

Math  Reiny, Saturday, February 6, 2010 at 4:27pm
You did fine.
When you get c/0, where c is nonzero,
then the limit will approach infinity
It might be easier to see if you divide everything by only x^2.
then lim((3x^3  5x +2)/(4x^2 + 3))
= lim (3x  5/x + 2/x^2)/(4 + 3/x^2)
so as x approaches infinity you are left with 3x/4.
Now as x > ∞ the numerator 3x > ∞
and thus 3x/4 > infinity.

Math  Stuck, Saturday, February 6, 2010 at 7:50pm
Oh ok, thank you! My teacher taught us to divide by the largest power of x, so I didn't think of doing it like that.
But I don't quite get how c/0 is infinity. Isn't anything over 0 undefined?
Answer This Question
Related Questions
 limiting position of the particle  A particle moves along the x axis so that ...
 Calculus  Show that limit as n approaches infinity of (1+x/n)^n=e^x for any x&...
 Calc. Limits  Are these correct? lim x>0 (x)/(sqrt(x^2+4)  2) I get 4/0...
 calc  Are these correct? lim x>0 (x)/(sqrt(x^2+4)  2) I get 4/0= +/ ...
 Calculus  Show that limit as n approaches infinity of (1+x/n)^n=e^x for any x&...
 calculus  Help  I have three problems that I am stuck on  1. Lim x approaches...
 Calc Please Help  Are these correct? lim x>0 (x)/(sqrt(x^2+4)  2) I get 4/...
 General Calculus Question  How do you solve a limit when it approaches infinity...
 Calculus  How can I find the horizontal asymptote of: y=e^x/(2e^x+5) i know you...
 calculus  hi! just needed help on an FRQ for ap calculus ab. let me know if you...
More Related Questions