Limit ProblemDate: 16 Jul 1995 02:59:45 -0400 From: Anonymous Subject: Limits From: Daniel Chavolla Question: Could you please help me find this limit? lim x^2 + 2x x --> infinity ------- 5x - 5 I know that the answer is 1/5, but how? Thanks. Date: 17 Jul 1995 10:12:27 -0400 From: Dr. Ethan Subject: Re: Limits Hello Daniel, Are you sure that the x isn't squared on the bottom? Then the answer would be 1/5. I will show you how you could get 1/5 if the problem were slightly different. If it was: lim x^2 + 2x --------- x-> inf 5x^2 -5 Do you know that we can multiply the top and bottom of a fraction by the same thing and not change the value? I hope so, because that is what we are going to do. We can multiply the top and bottom by 1/x^2 - then the fraction will look like 1 + 2/x -------- 5 - 5/x^2 So now we can take the limit of this. 2/x will go to zero and so will 5/x^2, so all that is left is 1/5. Did follow that? If not then write back and I will try again. Ethan Doctor On Call |
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